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 Resources - FAQs


Parvalux Electric Motors - FAQs

The sections below show the answers to the questions that the Parvalux team are most commonly asked.

Hopefully all of your questions have been answered below, but if not, please contact our team by email at or by phone on +44(0)1202 512575



Can I buy Parvalux products from anyone else? 
We are represented by many official sales partners around the world, all of whom are fully conversant with our full range of products. Click here to view our distributor network.

What do I do if I am in a country with no approved distributor?
You can buy directly from our UK headquarters.

Where are you located?
Our main manufacturing facilities are based in Bournemouth, UK with a low-quantity manufacturing facility and our service centre based in Birmingham, UK.

What is your pricing policy?
Generally speaking the higher the quantity, the lower the price per unit. Our standard tariffs cover 5 to 1000 pieces; quantities over 1000 pieces are priced on a case by case basis. For quantities less than 5 please contact your local distributor.

How long will it take for my order to arrive?
If the product you require is in stock we can generally deliver within 5 working days. If the product has to be manufactured our delivery times vary from 6 - 8 weeks, depending on the specific design and the size of the order.

Do I have to have an account with you?
No. We can accept payment by cheque or card (Visa, MasterCard or Switch).

What are your credit terms?
To all account customers we offer 30 days credit from date of invoice as standard. Credit limits are set on a case by case basis.

How do I set up an account?
We require two trade references and a bank reference before we can process your application.

What are your terms and conditions?
Please click here to view our Terms and Conditions.

Are your products covered by a warranty?
All Parvalux new products are guaranteed for a minimum period of 12 months, from date of invoice, against electrical breakdown or mechanical failure resulting from defective materials and/or workmanship; providing the failure is not due to misuse or operation under adverse conditions (including use with non-Parvalux approved controllers). Carbon brushes, capacitors and flexible cables are not covered; units that have been dismantled in any way, or if the nameplate/product label has been damaged/removed, will invalidate the guarantee. Please refer to our terms and conditions for more detail.

What is your returns policy?
Any unit proving faulty and covered by the provisions of warranty must be returned to us complete, with carriage paid, for examination to be repaired or replaced at our discretion. NB: before returning items please call a member of our sales team to obtain a returns (RMA) number. All returns must be clearly marked with their RMA number and sent to: Returns department, Parvalux, 490 Wallisdown Road, Bournemouth BH11 8PU, UK. Please refer to our terms and conditions for more detail.



Where can I find technical information on your products?
We publish technical data on our website in html and pdf format. If you cannot find what you are looking for, please contact our Sales team via email:  or telephone: +44 (0)1202 512575.

Can I order a printed catalogue?
Yes. Simply click here to request one from our sales team

How many motor-gearbox configurations do you offer?
Our range offers in excess of 5000 standard motor-gearbox-ratio combinations.

That's a lot of products - where do I start?
There are a number of places on the site that focus on certain motor and gearbox types. Either navigate through the menus at the top of the page, click here to view our catalogues, or click here enter your requirements direct to our sales team who will get back to you with a suggested product.

Do you make products over 1kW?
We specialise in design and manufacture of sub 1kW electric motors. However, some of our products can be powered over 1kW for intermittent duty applications.

Do you make stepper motors?

Do you make motors for servo applications?
Although not true servo motors, our range of DC brushless units may be suitable for many servo applications, please call a member of our sales team to discuss your requirements.

Do you make coreless, ironless or micro motors?

Do you make precision products?
Our HP range of planetary gearheads can be used for many precision applications, please call a member of our sales team to discuss your requirements.

Can I fit a Parvalux gearbox to a competitor's motor?
Generally we only sell our gearboxes as part of a complete unit due to the nature of their integrated sealed design. However, we do have products which are suitable for mounting onto a 3rd party motor, for example, the GB4, GB9, GB12 worm gearboxes as well as the HP60 planetary gearhead; please contact our sales team for more information.

Can I fit a competitor's gearbox to a Parvalux motor?
Yes, we offer a range of motor output flange options to enable you to fit a wide range of industry standard gearboxes to our motors.

Do you make high-efficiency gearboxes?
Yes, the GB worm-wheel range offers a theoretical efficiency of 95% at ratio 12.5:1, and the HP planetary range offers efficiencies in excess of 95% at ratio 4:1.

Do you sell speed reducers?
Yes, the HP range of high efficiency gearboxes can be configured and supplied as stand-alone speed-reducer units.

Can you help me decide which motor-gearbox is right for me?
Yes. However we cannot take ultimate responsibility for your final selection, you should always obtain a second opinion if in doubt.

What information do I need in order to select the right product?
You can visit our 'Choosing Your Motor' page or alternatively, we will need to know:

1. The type of machine or application it is intended for

2. The speed requirements (rpm)

3. The required torque (Nm)

4. The type of power supply (AC single, three phase or DC)

5. The voltage required

6. The shaft orientation (in-line or right-angle)

7. The operating conditions (stop-start or continuous) 8. the overall environmental and physical conditions

What if I don't know the torque or power requirements?
In most instances we can calculate the theoretical torque / power requirements.

What are the standard options for gearboxes?
The options available will depend on which product you opt for. Generally speaking, we offer single, double or hollow shafts with keyways or flats; gearboxes with base fixings; and 3 or 4-point output flange fixing arrangements.

What are the standard options for motors?
The options available will depend on which product you opt for. Generally speaking, we offer tachometers, brakes, encoders, controllers and terminal boxes with many of our products.

Can you customise a product for my application?
Absolutely! We offer many non-standard customisation options to enable our products to fit your application. This service enables customers to specify their preferred motor, gearbox, shaft, spindle, paint finish, fixing arrangements, ratio, ingress protection (IP) rating, gear material and lubricant in order to realise their preferred solution. This is generally available at no cost premium on orders over 1000 units.

Can you design a motor and gearbox for me if I cannot find what I'm looking for?
Absolutely, we specialise in designing bespoke motor-gearbox solutions for your application. This service enables customers to outline any number of mechanical, electrical, environmental or even aesthetic requirements in order to realise their preferred motor-gearbox solution.



Where can I find wiring diagrams for your AC motors?
You can request a wiring diagram from our sales team

Can more than one motor be operated from a single control?
Operation of more than one motor from a single controller is not normally recommended as it offers less protection to the controller and the motors in the event of a fault such as a mechanical overload. However more than one DC permanent magnet motor may be operated with most types of controller as long as the sum of the motor currents does not exceed the rated output current of the controller.

What is meant by the term self-locking?
The tendency of gearing to resist movement when the motor is at rest and the load is attempting to move. Self-locking gearing is not a recommended method for preventing movement in applications where the movement may cause injury or damage; an external brake is recommended in those instances.

Which gearboxes are self-locking?
Right angle gearboxes with ratios greater than 25:1 (or 50:1 with plastic gears) will usually resist movement up to their torque rating. As the physical size of the gearbox increases, the lowest ratio at which self locking occurs increases. Please contact us for more information.

Can continuous duty motors be used intermittently?
Yes, however operation at loads higher than the nameplate rating is only possible for short periods as long as there are rest periods for cooling. Loads must not exceed the mechanical rating for the gears and the temperature of the motor should be tested to make sure it will not overheat.

Which motors are electrically reversible?
All of our products are reversible except AC induction shaded pole motors; however, some require a full stop before reversing. Series or shunt wound motors are not reversible when wired with optional 2-lead configuration.

Will a DC brushless motor function without a controller?

Can I run an AC motor on a DC supply and vice versa?
An AC series wound motor will run on a DC supply at a higher on load torque and/or speed. Other types of motor will require a transformer and rectifier, or an inverter, depending on the type of motor and supply.

Is an adjustable speed system ever appropriate for a single speed application?
Yes, particularly if the desired speed is not known until the motor is installed, or in the case of a brushless motor and controller being used to maintain a constant speed to a greater degree than possible with a permanent magnet motor with no controller.

Can single speed motors ever be operated as variable speed?
Most induction motors may be operated as variable speed with a frequency inverter. DC shunt wound and permanent magnet motors can be operated as variable speed using a thyristor or PWM controller.

What is axial load?
Axial load is a force on the output shaft into or out of the motor or gearbox. Exceeding the allowable axial load will cause premature wear on output shaft bearings and gearing or even mechanical failure.

What is radial load?
Radial load is a force pushing or pulling the side of the output shaft, which may be the result of weight, tension or transmitted torque on the shaft. Exceeding the allowable radial load will cause premature wear of output shaft bearings and gears and could cause the shaft to break. Figures are based on 10mm from motor mounting face with plain shaft extension.

What is backlash?
The clearance between mated gear teeth, measured along the pitch circle in arc-minutes.

How many arc-minutes are there in a degree?
60 arc-minutes

How many Watts are there in one horsepower (hp)?
746 Watts

What is a NEMA flange?
A square fixing arrangement that conforms to the standards set by NEMA (The National Electrical Manufacturers Association).

What is an IEC flange?
A circular fixing arrangement that conforms to the standards set by the IEC (The International Electrotechnical Commission).

What is a metric/Euro-standard flange?
A motor-face flange designed to interface with a wide range of European gearboxes.

What is an S1 duty cycle?
Continuous duty. The motor is capable of operating at the stated load continuously.

What is an S2 duty cycle?
Short term duty, expressed in terms of a time period. The motor is capable of operating at the stated load for the time period stated, and then should be allowed to fully cool before further operation.

What is an S3 duty cycle?
Intermittent periodic duty with short on-off cycles, expressed in terms of a percentage. The motor is capable of operating at the stated load for the percentage of time stated. The remainder of the time it must be stationary and not powered. The on time must not be long enough to allow the motor to overheat, and not so short as to allow the starting current to significantly affect the temperature rise. In general, for a DC permanent magnet motor with a duty cycle of S3 ×%, the rated torque is equal to the continuous torque multiplied by 1/√( ×/100).

What is momentary overload?
The torque the gearbox can withstand for a very short period of time (less than 15 seconds) i.e. its start-up torque.

What does insulation class F indicate?
 Insulation class F indicates the capacity to withstand a maximum temperature rise of 115°C at a maximum ambient temperature of 40°C.

What is RoHS?
RoHS stands for the 'Restriction of Hazardous Substances'. It is a European Directive that restricts the use of mercury, lead, hexavalent chromium, cadmium and a range of flame retardants in the production of electrical and electronic equipment.

What is a PWM controller?
Pulse-width modulation (PWM) controllers work by switching the supply to the motor on and off very rapidly. The average power that this switching frequency produces affects the speed at which the motor turns, so by adjusting the frequency (pulse-width) the speed of the motor is also controlled. PWM is a powerful technique for controlling analogue circuits with a digital signal.

What is a dog clutch?
A type of clutch that gives the operator the ability to manually disengage the gearbox drive shaft from the drive unit. The mechanism is mounted externally and forms part of the gearbox output shaft.

What is a de-clutch?
A clutch that gives the operator the ability to manually disengage the gearbox drive shaft from the drive unit. The mechanism is mounted internally and forms part of the gearbox output shaft.

What is Delrin?
Polyoxymethylene (POM). It is a lightweight, low-friction, wear-resistant thermoplastic capable of operating in temperatures over 90°C. Delrin is the brandname of the variant manufactured by DuPont. Other industry equivalents are normally referred to as 'composite' or 'plastic' gear materials.

What is a Dynamometer rig?
A machine used to measure torque and rotational speed (rpm) from which the power produced by a motor can be calculated.

What is an FMEA test?
Failure mode and effects analysis (FMEA) identifies potential failure modes within a system and the consequences of those failures. Failure causes are any errors or defects in process, design or application, and can be real or hypothetical.

What is an EMC test?
Electromagnetic compatibility (EMC) checks for unwanted Electromagnetic Interference (EMI) that operating different equipment in the same environment may incur and the avoidance of its effects.

What is rapid prototyping?
The use of modern computer aided manufacturing techniques to significantly accelerate the product development process, such as vacuum metal/silicon casting, fused deposition modelling, stereo-lithography apparatus and selective laser sintering/melting. Please click here for more information.