Glossary of Terms

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We’re always happy to answer any questions you might have about industrial fans and electric motors – but if you’d like to learn for yourself we’ve put together a glossary for you!


Axial – Axial Fans (also known as ‘Prop fans’) are fans that have blades similar to that of an aeroplane – it’s easy to remember the word axial as all impellers have an axis…. axial-impellers-001


Basket fans – An axial fan which looks like it’s been mounted in a basket, such as a guard mounted fan like these: basket

Bifurcated fans – Essentially a long-cased axial fan, which is split into two around the motor instead of passing directly over it. Often used when the motor needs to be protected against heat or destructive substances.

A Bifurcated Fan 001

Cased fans – Fans which are in cylindrical cases! May be long cased, short cased or bifurcated.

Centrifugal fans – A fan that uses centrifugal (outward) force to rotate the air in a case or a system. Applications can vary due to the type of impeller, whether it be for moving large quantities of air or moving air at a higher pressure. Centrifugal fans are also often quieter than axial fans.CentrifugalFan

Chip shop fans – Many chip shop range manufacturers use a centrifugal fan to ventilate the range, such as Hopkins, Henry Nutall, Ellidge & Fairley, among others. Often they use a B56 Motor to power the centrifugal impeller which goes in the fan unit. Tthe impeller itself looks a bit like a hamster wheel.


Contra-rotating – Two single stage impellers which are rotating in opposite directions but send the air in the same direction, incre

asing the pressure of the fan unit.


Extractor fan – Quite simply, a fan which extracts air, fumes, dust, etc. Most fans are extractor fans, unless they are air input fans, but even they extract air from outside to in!

Fan speed controller – Literally controls the speed of the fan! Can be used with single phase units from 1Amp to 6Amps. If you have a three phase unit you can use an inverter instead, but they tend to be more complicated and expensive.

Guard mounted  See “basket fans”

Impellers – All fans have impellers! Axial impellers (that look like propellers), Centrifugal impellers (that look like hamster wheels), backward curved impellers (complicated looking things that shift lots of air) and Pressure fan impellers (that have  a large diameter with long blades sandwiched between two narrow plates), among others.


Inline fans – A fan which is mounted inside the duct you’re using to extract air, therefore it is in-line with the airflow you are creating using the fan.

Man Coolers – A floor standing fan unit that is often used in factories to cool down the workforce. Beyonce uses a man cooler on stage so that she can keep cool and also keep her locks flowing whilst shaking her booty!


Multivane fansLooks like a hamster wheel fan – see impellers! Also see Chip Shop Fans

Plate fans – A fan which is mounted onto a plate for support before being mounted on a wall or inside a roof fan.


Roof fans – Extractor fans which are mounted on the roof of the building to extract rising fumes and dirty air. Often used in welding shops and warehouses.




B56 – A standard imperial fractional horsepower motor, no longer manufactured in the UK but still widely used, especially on lathes, chip shop ranges and potato rumblers as well as many older engineering tools.

B56 Motor

Electric motor rewind – Hopefully, in physics or technology in school you made a crude DC motor with copper windings and magnets. All motors have copper windings which can get damaged for many, many reasons. Sometimes a motor can’t be replaced, so it needs repairing and if the windings are damaged, the motor will need a rewind!

Fractional motors – Fractional indicates that the motor’s power rating is smaller than one horsepower and measured in imperial fractions. B56s are an example of this.

Geared motors – Geared motors are used mainly in applications where a motor needs slowing down and regulating, like on a conveyor or a large mixer. Often a geared motor can improve the torque of the unit as well.

IEC – A European dimensional standard that all metric motors are designed to.

Multi-fit – A small motor like the type used in commercial fridge fans, there are many ways to fit it, hence multi-fit!

Single phase – Domestic supply..Suitable for domestic requirements, light commercial usage is generally up to 2.2kw (3hp) maximum or a maximum currant (amps) of 10Amps

Step motors – a type of brushless DC motor which separates the full rotation into equal steps, making it easy to monitor during use with an encoder.

Three phase – Industrial Supply. used to power large motors, fans, pumps and industrial application.



Coolant pumps – Also known as a ‘suds’ pump. Often used on milling machines and lathes to pump the coolant (or suds) around the machine.

Direct On Line starter. A motor starter that safely starts and stops an electric motor, as well as protecting the motor from burning out using an overload that cuts off the power to the motor if becomes overloaded. Using one can help a motor last much longer and stop it from burning out, thus preventing a rewind.

Horsepower – A unit of measurement for power: one horsepower in electric motors is equal to 746 watts or 0.75kw

Inverters – A unit which can control the frequency of a motor, and therefore the speed.

Torque – A unit in Newtons that measures the strength of the power of the unit. If a geared motor has more torque it has more strength. If a car has more torque it can pull a heavier load or apply more traction as well as speed.


If you’d like to know more about electric motors, have a look at our guide which answers all your questions, from “Who invented the electric motor?“, “How does an electric motor work?” to “Where are electric motors used?