Did you know that 2% of motor failures are due to the shaft coupling?

Here are the reasons why:

1. Misalignment

  • A coupling that is badly aligned suffers unusual load stresses and can lead to failure.
  • Ensure the coupling is aligned parallel to the shafts.

Tips: Check all 3 types of alignment of your motor

Mechanical alignment: Experience has shown that any base-mounted assembly of motor and driven load, no matter how rugged or deep in section, may twist out of alignment during shipping or moving, and that alignment by eye is ineffective. Proper alignment of direct-coupled drives can be accomplished by a dial-indicator, laser, or computerised instrumentation.

Parallel misalignment: This is the offset between the centrelines of the two shafts. This can be determined by mounting a dial indicator on one coupling half with the indicator probe bearing radially on the other coupling half, and then rotating both shafts together through 360 degrees.

Angular misalignment: This is the amount by which the faces of the two coupling halves are out of parallel. This may be determined by mounting a dial indicator on one coupling hall with the indicator probe on the face of the other half, and then rotating both shafts together through 360 degrees to determine any variation in reading. During this check, you must keep the shaft of a motor with endplay against its thrust shoulder and the shaft of a driven load with endplay against its thrust shoulder to prevent false readings due to shaft movements in the axial direction.


What is the best way to ensure my coupling is aligned correctly?

Laser alignment is the best way to ensure accurate alignment. Contact your coupling manufacturer for the alignment tolerances for your coupling.

2. Bad installation

  • The biggest cause of coupling failure is due to incorrect mounting.
  • Research and use appropriate fitting techniques for your motor.

There are two main types of couplings available:

  • Rigid couplings – for use when shafts are coaxially aligned.
  • Flexible or compensating couplings – for use when shafts alignment cannot be guaranteed or there is expected distortion or movement that could be transmitted through the shaft


  • When installing a shaft coupling, ensure that you are using the correct coupling type.
  • If there is a degree of distortion or shock expected through the shaft, then a flexible coupling should be used.


Can rigid couplings be used on misaligned shafts?

Rigid couplings should not be used on misaligned shafts. Misalignment could generate lateral forces which could lead to premature failure of the shaft, bearings or couplings from wear and metal fatigue.

Do you know what are the other reasons for motor failure? Our 60 Minute Guide to Motor Maintenance is designed to give you, the engineer, all the information you need in industrial electric motor maintenance in a format that is concise, easy to understand and is a point of reference for now and the future. Visit our website and request your Free Guide: 

We provide 24/7 Technical Support to engineers, our dedicated Support line is available 8am – 5pm every day, manned by one of our fully qualified engineers.

If you need further assistance on how to prevent your motor from failing, call us, day or night, on 0330 9000 247.

What you should take into consideration when choosing Motor Cables for Variable Speed Drives

The motor cable for a PWM variable speed drive can have some unexpected effects. In this Blog Post you can find some special considerations which are needed when choosing and installing a motor cable for a VSD.

Current rating

The steady-state loaded motor current is not appreciably changed by using a VSD with the motor. The motor current protection function in the drive is approved (e.g. by UL) for thermal protection of the motor and cable in the event of an overload. Therefore the basic current rating of the motor cable is the same as for a motor connected directly on line.

Cable sizing and voltage drop – cable sizing codes

Cable sizing codes used by electrical installers, including cable planning software packages, often have special provisions for motors. These would be based on a standard industrial induction motor started by direct connection to the power line (“Direct On Line” DOL starting). Long cables may need to be larger than would be dictated by the continuous full-load current rating, so as to restrict the voltage drop in the inductance and resistance of the cable during starting. A typical industrial induction motor draws a DOL starting current of about 5 times its maximum rated value, because of the high slip before it reaches its running speed; and during starting the available torque is not particularly high, as illustrated in Figure 1. It is possible for excessive voltage drop in the cable to result in the motor failing to start if the load torque is sustained at low speed.

Figure 1: Current and torque during starting an induction motor directly on line

When using a variable speed drive the motor slip is always low and the current during starting never exceeds the short-term rating (e.g. 110% or 150% depending on the application). Also, the drive can be tuned with the motor and its cable so that the cable voltage drop is compensated – at a speed below base speed there is voltage headroom available between the capability of the drive and the voltage required to achieve the working flux density in the motor. Therefore with a VSD there is no need to over-size the cable to reduce voltage drop at starting. In installations with long motor cable runs this fact can allow considerable savings in cable costs. When using cable-sizing software for planning an installation, the motor with VSD should be set as a simple resistive load, not a motor, in order to avoid the unnecessary allowance for motor starting current.

Types of cable – screening (shielding)

The VSD output uses Pulse Width Modulation (PWM) to create a supply with adjustable voltage and frequency to control the motor. The pulses have fast edges, with rise/fall times in the order of 100 ns. This means that the frequency content of the voltage in the motor and motor cable extends up to high radio frequencies – generally there is a very high level for frequencies up to around 10 MHz, and a considerable level up to around 50 MHz. In order to avoid electromagnetic interference (EMI) the cable needs to be screened so that emission of electromagnetic energy is suppressed. The presence of a grounded screen prevents electric field emission, and the correct connection of the screen at both the motor and inverter ends, using a bond with minimum self-inductance, prevents magnetic field emission. Both are necessary.

The possible emission from a wrongly managed motor cable can affect both radio frequency communications and nearby electronic equipment such as sensors and data circuits, which are sensitive to disturbances in these frequency ranges.  The Electromagnetic Compatibility (EMC) standard for drives IEC 61800-3 (EN 61800-3) requires the motor cable to be screened, otherwise the drive output would have to be connected through a very expensive and unwieldy radio frequency filter device.

Practical tests have shown that cable screens using steel or copper can be equally effective provided they have good continuous coverage and continuity along the length of the cable. This facilitates radio frequency current flowing along the screen to cancel the magnetic field caused by the common-mode current in the power cores, illustrated in Figure 2.

Figure 2: Cancellation of external magnetic field by a screened cable with screen connected at both ends

Grounding (earthing)

The motor ground connection is primarily to ensure safety in the event of a ground fault in the motor. The ground connection has to carry the fault current until the safety device (fuse or circuit breaker) interrupts the current, whilst ensuring that the touch voltage of the motor body remains within safe limits. Normally the VSD limits the ground fault current to much lower levels and shorter durations than a fuse or circuit breaker. However it relies on complex semiconductor devices and circuits to achieve this, which might fail. For safety reasons therefore the ground loop impedance for the ground connection needs to be the same as if there were no VSD – ultimate protection is provided by the upstream protection device feeding the drive. The choice of ground conductor dimension is exactly the same as for a directly fed motor. This is illustrated in Figure 3.

Figure 3: Motor ground fault path and touch voltage

As explained above, the motor cable for a VSD needs to be screened.  Whether this screen can also provide the safety ground connection depends on its impedance and on the code of practice used for grounding. It is common to use a separate copper ground conductor in order to avoid the need for a special calculation.

The question sometimes arises, whether to use a ground core within the screened motor cable (i.e. a 4-core cable) or an external one. From the point of view of safety, both solutions are equally good. For EMC reasons also, both methods can work, but care is needed with a 4-core cable. The ground core carries quite a high noise current, picked up from the power cores inside the cable. If it is taken to a point in the inverter wiring panel away from the cable screen termination, it will inject the noise current into the panel ground wiring, with a risk of disturbing signal circuits. It should be connected to the inverter panel physically very close to the screen termination, as shown in Figure 4.

The question sometimes arises, whether to use a ground core within the screened motor cable (i.e. a 4-core cable) or an external one. From the point of view of safety, both solutions are equally good. For EMC reasons also, both methods can work, but care is needed with a 4-core cable. The ground core carries quite a high noise current, picked up from the power cores inside the cable. If it is taken to a point in the inverter wiring panel away from the cable screen termination, it will inject the noise current into the panel ground wiring, with a risk of disturbing signal circuits. It should be connected to the inverter panel physically very close to the screen termination, as shown in Figure 4.

Figure 4: Correct management of ground (PE) core in 4-core screened motor cable

Capacitance and inductance

The motor cable has natural self-capacitance and inductance. At power frequencies the capacitance has negligible effect, whilst the inductance causes a small voltage drop which is mainly negligible except for very long cable runs and high DOL starting currents.

The effect on the fast-rising PWM pulses from an inverter is much more important. At every pulse edge the cable capacitance must be discharged. This results in quite large, but short, current pulses at every edge. These can cause high-frequency field emission, and also they form a load on the inverter power semiconductors during switching.

Fortunately the cable inductance is distributed along the cable with the capacitance, and has the effect of limiting the charging current. The net effect is described by the “Telegrapher’s equations” and results in cable parameters Z0, the characteristic impedance, and v, the propagation velocity.

At each PWM pulse edge, a current flows to charge the cable, given by:

Where VDC  = DC link voltage of inverter

For a coaxial cable the characteristic impedance is given by:


  = relative permittivity of dielectric (insulator)

  = Inside diameter of outer conductor

  = Outside diameter of inner conductor

In a 3-phase screened cable the geometry is not a simple coaxial shape, but its behaviour is similar, the impedance being a function of the dielectric permittivity and the relative diameters of the inner and outer conductors.  The geometry and dielectric material used in cables does not vary greatly, and the logarithmic term   means that the impedance is not very sensitive to geometry changes. Measured values of  for standard screened power cables range between about 45 ohm for 2.5 mm2 cable to 15 ohm for 120 mm2cable. This means that for larger drives with current ratings over about 20A the charging current is insignificant, but for ratings below about 10A it has an impact and the drive has to be designed to supply the charging current without excessive power loss, or of unwanted over-current tripping.

The duration of the current pulse is determined by the length of the cable, it is equal to the time for the pulse to travel to the motor end and then return as an inverted reflection. The longer the cable the greater the effect on the inverter. Some special cables can have abnormal values of .

The ratio of diameters can be much reduced if there is no insulating jacket between the power cores and the screen, which may occur for highly flexible screened power cables. Mineral insulated copper clad cable (MICC) also has a low ratio of diameters, and the permittivity of the mineral insulator is high, so the impedance is very low.

Another situation where the effective  will be low is if several cables are connected in parallel to achieve the required current rating, rather than use a single large-diameter cable. In these cases, unless the total cable length is very short it is often necessary to add series chokes between the drive and the cable to restrict the cable charging current. In Control Techniques we have occasionally encountered a case where the installer has used three cables in parallel and has used one cable with three cores for each phase. This arrangement is bad practice in any case because the mains frequency current in the phase cores induces counter-currents in the screens, which can result in heating of the screens. When used with a VSD it results in an exceptionally high stray current from the excessive capacitance between the power cores and ground, which can cause high-frequency interference with nearby circuits and also risks over-loading RFI filters through excessive common-mode (ground) current. The right and wrong methods are shown in Figure 5.

Figure 5: Right and wrong methods for connecting power cables in parallel

In the above I have not particularly distinguished the modes in the cable to which the impedance applies. It is generally not necessary to consider this much detail, but the main modes which affect the drive are:

  • Simple asymmetric mode, one core relative to all other cores and screen. This is relevant to drive loading but not to ground current or filter loading.
  • Common mode, all power cores to screen and to ground core where fitted. This is relevant to ground current and filter loading.

Motor voltage overshoot and rate of change (dv/dt)

The cable capacitance and inductance causes voltage overshoots at the motor terminals at the pulse edges. In terms of the Telegrapher’s equations, these can be understood as reflections at the motor terminals caused by the mismatch of impedance. Even quite short cables result in some overshoot. This can be surprising if you are unfamiliar with inverters and fast-changing pulses – on a microsecond timescale the voltage at the motor is quite different from that at the inverter even though they are connected together.

Motors have a voltage withstand capability which depends on the voltage rise-time. For rise-times below about 0.8 microseconds the voltage withstand may be reduced because the voltage tends to be concentrated into the first turns of the winding, and stresses the interturn insulation.  Most motors are designed for use with inverter drives running from a 400 V or 480 V supply without special measures. For 690 V motors it is strongly recommended to use a purpose-designed inverter-rated motor to avoid any risk of premature insulation failure. Such motors should be specified in compliance with the guidance given in IEC document TS 60034-25 (“Guidance for the design and performance of a.c. motors specifically designed for converter supply”).

Multiple motors

Occasionally it is desirable to operate a number of motors from a single drive. For example, small ventilation fans may be fitted around a building and driven from a single drive, each with its own cable. In this situation the capacitance of the cable is dictated by its total length, but the inductances of the sections appear in parallel to the drive, not in series. For n cables the impedance seen by the drive at its pulse edges is Zo/n

A series choke should be used in this case to restrict the capacitance charging pulses, otherwise the drive is likely to suffer from premature over-current tripping or limiting caused by the high charging current.

Source: The Automation Engineer, Control Techniques.

We are the Official Service Partner for Controls Techniques and can provide 24/7 Technical Support on all Controls Techniques drives. When you have a breakdown give us a call, day or night, on 0330 9000 247 or send us an email: service@quantum-controls.co.uk

As an ABB AVP for Motors we can offer you Sales & Support for Motors. You can either call us on 0330 9000 247 or send us an email on: service@quantum-controls.co.uk.

Join the team at Quantum!

Here are a list of our current vacancies at Quantum, if you would like more information on any of the roles, feel free to email us at hr@quantum-controls.co.uk or give us a call on 01661 836 566.

We are always on the look out for excellent Drive Service Engineers to cover our Contract Customers across the UK, so even if we don’t have it advertised below, please feel free to still send your CV to hr@quantum-controls.co.uk. Our Service Engineers are based all over the UK so don’t worry if you aren’t near one of our Head Offices.

Drive Service Engineer – South East Area

Drive Service Engineer – Yorkshire

Hire Sales Engineer – South East/London

Sales Engineer – Scotland

Drives and Machine Safety

According to a commonly consulted hierarchy of controls, people’s safety in the workplace is dependent on various types of protective measure. The most effective of these is classed as hazard removal – obviously enough. At the other end of the scale is the wearing of personal protective equipment. Midway between the two lies the field of engineering controls – the design or adaptation of machinery to isolate the worker from risk.

This category comprises a broad variety of engineering ideas. Lifts and platforms help keep people from falling (or from being fallen onto). Sacrificial parts such as fuses or rupture discs are designed to protect machines by failing under stress. Ventilation systems make sure atmospheres are clean and safe to breathe.

Machine safety systems in manufacturing

Machines with rapidly moving parts, such as flywheels, drive belts and fan blades, pose a particular hazard, and, where they are feasible, guards to prevent contact with body parts are a legal requirement. These guards range from appropriately fabricated hoods and shields to, in the case of robots and other larger machines, wire perimeter cages.

Where human intervention in the equipment is called for, in order to carry out inspection or repair, it is essential that dangerous machinery is deactivated and kept safely turned off. A number of devices are traditionally used to carry out this procedure. Most commonly, electrical interlocks attached to access gates automatically disable machinery when gates are opened.

Light bars and curtains perform the same function for smaller machines or where mesh cages would otherwise be inappropriate. (The electrical circuit is interrupted when a person breaks a field of light projected between two points.) Pressure mats are another frequently used presence detection device.

Such a safety system conventionally operates by means of a series of hardwired electromechanical components: switches, relays, contactors, encoders and so on. Increasingly, however, the safety controls enacted by these external devices are being integrated into the programming of variable-speed drives.

Drive-based safety systems are less complicated and time-consuming to install than their non-digital predecessors. They avoid the additional electronic structures required by traditional fail-safe mechanisms and are less vulnerable to parts failure. With simpler and speedier reset procedures, moreover, expensive downtime can be minimised.

Drive-based safety systems in manufacturing machines

Like all aspects of machine engineering, drive-based safety functions must operate to a certain level of reliability. Standards devised by bodies such as the International Electrotechnical Commission inform legislation produced by the European Union and other authorities around the globe. In order to meet the safety criteria required by the EU Machinery Directive 2006/42/EC, the functional safety of variable speed drives must accord with product standard EN/IEC 61800-5-2.

The safety measures a drive-based system can bring to operations cover a range of hazard responses. The fundamental function, and that most commonly used, is the Safe Torque Off (STO) signal. This simply switches off the torque-generating energy supply to the motor. How quickly the machine stops will depend on load or friction, and it is guaranteed against unexpected restart.

Where mechanical action must be halted in a controlled manner the Safe Stop 1 (SS1) function instructs the drive to ramp speed rapidly down to a standstill before automatically activating STO. This suits the emergency stop requirements of heavy spinning equipment such as saws, grinding machines and rolling mills.

Safe Stop 2 (SS2) works in the same way except that, after braking, the motor is held in a Safe Operating State. Using this function to keep full torque available from the motor may be necessary to hold equipment parts steady that would otherwise fall out of position.

In the case of machinery such as cranes and hoists that deal with very heavy loads a Safe Brake Control (SBC) is used to activate a mechanical holding brake at the same time as the main drive is deactivated by the STO signal.

Thanks to the Safely-Limited Speed (SLS) function, machinery can be made to run below a specified limit. As monitored by the drive, a speed that exceeds that limit will automatically trigger an emergency stop through an STO or SS1 signal.

The SLS function is particularly useful in the set-up and maintenance of equipment where, for example, cables need to be manually fed over turning wheels or drums. It is also generally a way of minimising loss of work. Rather than shutting a machine down completely when an operator is in the vicinity of equipment, it can be used to proceed with production at a reduced, safe rate until the operator enters a specific danger zone (at which point power is cut).

And because sharp drops, as well as surges in power, can cause some machines to behave dangerously, a lower speed limit may be programmed in conjunction with an upper limit by means of the Safe Speed Range (SSR) function.

Having this range of safety controls available, individually or in combination through plug-in modules and fieldbus modules, gives the automation designer significantly more flexibility and freedom than previously. And with status information available in the drive interface, the operator has a reliable system overview extending to timely and accurate diagnostics.

Its intelligent and adaptable character ultimately means that a drive-based safety system is as capable of pre-empting mechanical dangers as it is effective at responding to them. The consequent benefits to the workplace, not just in terms of safety but in those of streamlining design and enhancing overall efficiency, make it a natural component of automated industry.

Source: The Automation Engineer, Control Techniques.

We are the Official Service Partner for Controls Techniques and can provide 24/7 Technical Support on all Controls Techniques drives. When you have a breakdown give us a call, day or night, on 0330 9000 247 or send us an email: service@quantum-controls.co.uk

Did you know that 16% of motor failures are due to external factors?

Here are the reasons why:

1. Motor operating temperature

  • The industry standard for LV motor insulation systems is class F, with a limit on temperature rise of class B.
  • Other insulation systems offering higher levels of protection are available.


  • Ensure that the cooling systems of the motor are suitably maintained.
  • Broken fans, clogged vents and blocked or damaged cooling fans can cause excessive heat build-up.
  • Check motor cooling regularly.

2. Humidity & Environment

Electricity and water are a bad mix; high humidity can allow moisture to enter the motor and cause damage and corrosion.

This can be combatted by: Opening drain hole plugs: fitting ant-condensation heaters; utilising addition corrosion protection; enhanced paint systems


  • Where motors are operating in harsh outdoor conditions, consider the effects of cold as well as heat.
  • Condensation heaters should be fitted to motors used outdoor in cold winter months to minimise condensation within the motor.


What do I do if I can’t seal completely against moisture ingress?

Ensure that breather plugs are fitted and are kept clear – this will ensure any moisture that does enter can drain away.

3. Contamination

Ingress of foreign particles into the motor enclosure can cause damage – particularly to a motors bearings or windings. Use the correct IP ratings to protect your motor.

Motor IP ratings explained: 3.5 Degrees of protection: IP code/IK code

Classifications of the degrees of protection provided by enclosures of rotating machines are based on:

  • IEC / EN 60034-5 or IEC / EN 60529 for IP code
  • EN 50102 for IK code

IP protection: Protection of persons against getting in contact with (or approaching) live parts and against contact with moving parts inside the enclosure. Also protection of the machine against the ingress of solid foreign objects. Protection of machines against the harmful effects of the ingress of water.

Tips – other basic measures to protect your motors against ingress are:

  • Labyrinth seals
  • Radial seals
  • Using IP56 or IP65 rated motors


What about protection against mechanical impacts?

IK codes outline the degree of protection of a motor against external mechanical impact.

4. Ambient temperatures

  • Ensure motors are rated for the ambient condition in which they operate.
  • Derating is often necessary for high ambient temperatures whilst low ambients may require special materials.

Check your motor is suited to its operating environment.


  • Basic motors are designed for operation in a maximum ambient temperature environment of 40º C and at a maximum altitude of 1000 meters above sea level.
  • If a motor is to be operated in higher ambient temperatures, it should normally be derated, as a guide use the table below.

Do you know what are the other reasons for motor failure? Our 60 Minute Guide to Motor Maintenance is designed to give you, the engineer, all the information you need in industrial electric motor maintenance in a format that is concise, easy to understand and is a point of reference for now and the future. Visit our website and request your Free Guide:

We provide 24/7 Technical Support to engineers, our dedicated Support line is available 8am – 5pm every day, manned by one of our fully qualified engineers.

If you need further assistance on how to prevent your motor from failing, call us, day or night, on 0330 9000 247.

We are hiring! Financial Controller vacancy available!

Quantum Controls are the largest supplier of variable speed drives, motors and associated services in the UK.

We are currently in a period of sustained growth and now have premises in Prudhoe, Thetford, Glasgow and a manufacturing facility in Birtley.

We have an exciting opportunity within our finance team for someone who is enthusiastic, driven and with an eye for detail.

You will be based at our Prudhoe premises and report directly to the Managing and Operations Directors. As Financial Controller you will:

  • Control and manage costs out of the business
  • Produce Monthly Profit and Loss Accounts and Balance Sheets by department and revenue centres
  • Ensure all Balance Sheets Control accounts are reconciled at month end
  • Reconcile Fixed asset register each month making sure that all assets have been disposed of or added correctly
  • Analyse the profitability of all jobs and provide feedback to the management team
  • Manage and Supervise 3 members of staff
  • Monitor the daily cash position and prepare weekly cash flow forecasts
  • Ensure the company has the required working capital for the business by ensuring stock levels are maintained at the required level and all debtors and application of payments are paid on time
  • Management of debtors balance and ensuring Credit Control is efficient and effective.
  • Manage the preparation of the year-end accounts including the completing of the audit file
  • Main Contact for Auditors
  • Completion and submission of VAT returns
  • Prepare Budgets and Rolling Forecasts
  • Manage and prepare Payroll for submission to the bureau, Year End and P11D
  • Contract Negotiations i.e. gas, electric, telephones, Waste disposal and IT contracts
  • Produce monthly Key Performance Indicators

£25,000 – £30,000 Salary, depending on experience.

If you are interested and would like to apply, please send your CV to hr@quantum-controls.co.uk.

We look forward to seeing your application!

What is Overall Equipment Effectiveness and how to calculate it?

The Overall Equipment Effectiveness (OEE) measures the manufacturing productivity by indicating the degree to which a manufacturing plant is truly productive. It can be used to monitor the efficiency of the manufacturing processes and help to identify areas for improvement.

This metric allows the identification of losses, benchmarking progress and improving the productivity of the equipment (minimisation of waste, improvement in maintenance, etc.).

1. Factors of Overall Equipment Effectiveness: Availability, Performance and Quality.

  • Availability includes anything that could cause the production process to stop, such as Unplanned and Planned Stops;
  • Performance takes into account anything that could cause any variations in the process causing delays or inability to run in maximum speed, such as Slow Cycles and Small Stops;
  • Quality takes into account any products or parts that don`t reach the quality standards, those that have any defects or require rework.

2. Calculating Overall Equipment Effectiveness:

  • 100% Availability means that the process is running within the planned production time without any unplanned or planned stops.
  • 100% Performance means that the process is running at its maximum speed, without any interruptions, such as slow cycles or small stops.
  • 100% Quality means there are no defected, scrap parts or elements that require rework.

We offer 24/7 engineering support, which means we are 100% available, any time, day or night, to help you improve the performance of your manufacturing process. Our wide range of Variable Speed Drives, Motors and Spares, as well as our service partnership with the major Drive manufacturers Danfoss, Mitsubishi, Nidec, Control Techniques and Schneider allows us to ensure we can respond to any breakdown you have.

If you would like any more information or further assistance, our engineers are only one call away, ready to answer any questions or enquiries you have. Simply contact us, day or night, on 0330 9000 247 for instant engineering support.

Redacted from: https://www.oee.com/

Control Techniques Appoints Quantum Controls as Service Partner for UK Service, Maintenance and Repairs

Control Techniques, part of the Nidec group of companies, today announces it has appointed a dedicated drives business, Quantum Controls Ltd., as a key partner to support its UK customer base.

Steve Lambert, Kevin Brown and Colin Edwards

Quantum is an accredited repairer of Control Techniques drives and under the agreement Quantum will offer a service, maintenance and repair contract for all Control Techniques drives, for past and current generation products. Quantum are able through this accreditation to support all families of drives including the Unidrive M Range which is a controlled repair product that can only be repaired through accredited repair centres. Customers can expect a fast response time and, with Quantum’s ability to offer repairs onsite, applications can be up and running again rapidly.

The agreement will also allow customers to replace failed drive technology from other manufacturers with the latest Control Techniques equipment, assuring trouble-free operation for years to come. It also offers a dedicated telephone support line during office hours where customers can speak directly with a fully-qualified variable speed drive engineer. Outside office hours, an ‘on call’ engineer is available to ensure 24/7/365 support.

Gareth Jones, Control Techniques and Nidec ACIM UK Country Leader – Nidec Motor Corporation said, “We are excited to announce this new partnership with Quantum Controls that will provide high levels of support for our installed products throughout the UK. As a dedicated drives company with multiple UK facilities, Quantum is uniquely positioned to serve and support our customers.”

Daniel Fitzsimmons, Sales Director at Quantum Controls added, “This is a significant step forward for Quantum and we expect to grow our customer base notably bringing the benefits of our technical expertise and high levels of service.”

You can download the Official Press Release from Nidec below.

Excellent Sales Engineer Wanted Now!

Could you be the next great Sales Engineer we are seeking to cover the South West/Midlands area?

Quantum Controls, the ‘UK’s Drives and Motor Supplier of the Year’ Winner for the last three years have been the UK’s largest Independent Supplier of Variable Speed Drives and support Services since 1994.

Our rapidly growing business is now looking for a new Sales Engineer to cover the South / Mid-West and Wales area.

Our Head Office is near Newcastle with Service Centers at Birtley, Leeds, Glasgow and Thetford with a further facility opening in the South in 2019.

Are you an excellent Sales Engineer / Account Manager with a proven track record? Are you tired of not earning large bonuses, doing the same job, feeling taken for granted? We can offer full product and sales training and a new career as a Variable Speed Drive and Motors Sales Engineer.

A loyal, customer focused, hardworking type of person, so good your last employer did not want to let you go…able to work on your own initiative and as part of a team…. A well-organized get-it-done type person?

If so, you should apply for this role. You just might be the next great addition to our existing team.

Excellent basic salary, company vehicle, iPhone, laptop, great holiday package, unlimited earning potential with bonus structure and a new career in a great working environment.

We don’t expect you to skip into work on a Monday morning, but we do want our staff to enjoy their working environment and have a rewarding daily working experience, we are not offering short term employment we want you to be part of our team for years to come.

Think you might be the person we are looking for? Then get in touch now e mail us today at p.stelling@quantum-controls.co.uk

Remember you don’t have to be a drives expert, full training will be provided…..don’t miss this opportunity it could change your life…. Salary / Unlimited Bonus. We will be offering a competitive benefits package and bonus. A full and Valid Driving License is required as a Company Vehicle will be provided. Basic + Bonus (OTE Circa £50,000)

Did you know that 16% of motor breakdowns are caused by a stator winding failure?

Here are the reasons why:

1. Over Heating

  • The cooler the motor operates, the longer its expected life…
  • A 10°C reduction in operating temperature typically doubles the motors lifetime.

Excessive starts are a major cause of over-heating. During a non-VSD start-up a motor typically sees between 6 to 8 times its rated current.

  • This increases the thermal status of the motor, increases thermal stress on the windings and can cause failure.
  • PTC Thermistors are a common protection method to protect against over-heating.
  • Thermistors have a positive temperature coefficient meaning that the resistance is increasing rapidly around the trip temperature. Connected to a thermistor relay this will trip preventing over-heating. Normal operating conditions will not cause this to happen.

How do I tell if the windings on a motor are under thermal stress?
Look for darkened areas on the motor windings, these marks are signs of over-heating.

2. Over Loading

  • Motor windings can fail due to over-loading at the motor shaft which causes excessive heat build-up and failure.
  • Fit thermal thermistor protection to guard against failure.
  • A thermal overload relay is a common protection method used to protect against over-load. It is a bimetallic strip that bends when over-loaded due to heat build-up.
  • Normal operating currents will not cause this to happen.


  • Connect thermistors to a thermistor relay in the motor control package and set the current overload limits to the rating plate FLC.
  • Follow manufacturer manuals for correct installation and limits for your motor.

We provide 24/7 Technical Support to engineers, our dedicated Support line is available 8am – 5pm every day, manned by one of our fully qualified engineers.

If you need further assistance on how to prevent your motor from failing, call us, day or night, on 0330 9000 247.