Frequently Asked Questions
Powerline Electric Motors has 35 years of experience
We have 35 years of experience in high-quality electric motor repairs and rewinding. This means we are well-placed to answer your questions about your electric motor. We follow industry-leading standards set by the Association of Electrical and Mechanical Trades (AEMT) and support the association's initiatives. Powerline focuses on energy efficiency, environmental care, and equipment lifespan through material reuse, recycling, and repair advice.
If you have a question you need answering, ask Powerline a question?
Which bearings are fitted in our motors?
Aluminium are fitted with either 2RS or ZZ NSK bearings throughout the range. Cast iron are fitted with standard re-greasable bearings which have no reference after, just the bearing number (E.G 6309 C3 instead of 6309 2RS C3).
What is a 7 series or angular contact bearing?
A 7 series bearing is also known as an angular contact bearing or a thrust bearing. The code for this would be 7316 instead of the standard 6316. They are bearings that have a higher weight carrying capability in comparison to a normal ball or roller bearing and we recommend that these are fitted 280 frame and above on motors that are vertically shaft down mounted (V1) on the drive end, to help withstand the weight of the motor’s rotor.
What is a NU bearing?
A NU or NJ bearing is a roller bearing. These are normally fitted in applications where side loads are excessive in comparison to the standard ball bearings rating. NU bearings are standard on our 4,6 and 8 pole motors in 315 and 355 frame. Roller bearings are available in other sizes and are always re-greasable so need to be fitted to a motor that has re-greasing tubes as standard.
What is an encoder and what does it do?
An encoder is a feedback devise that is fitted to the motor shaft. The idea of this is that the encoder senses the speed of the motor shaft and feeds this back to whatever software is installed on the other end of the cables. They are normally used when the exact speed of a motor is critical.
What is an insulated bearing?
An insulated bearing is a bearing that stops excess eddy currents from inverters travelling into the stator and potentially making the motor shaft live. The insulated bearing would normally be fitted on the none drive end of the motor and generally we would only fit one. We fit these on request but recommend that any motor 250 frame and above have these fitted when the motor is supplied by an inverter.
What does 2RS mean?
2RS means that the bearing is sealed for life with 2 rubber shields. ZZ or 2Z means that the bearing is sealed for life with two metal shileds.
An insulated bearing is a bearing that stops excess eddy currents from inverters travelling into the stator and potentially making the motor shaft live. The insulated bearing would normally be fitted on the none drive end of the motor and generally we would only fit one. We fit these on request but recommend that any motor 250 frame and above have these fitted when the motor is supplied by an inverter.
What is HTL and TTL on encoders?
HTL and TTL are the different incremental encoder signal types. Our standard range of W and S encoders are HTL (Push-Pull) signal but TTL (RS422) is available upon request on factory delivery times.
What is benefit of epoxy paint?
When it comes to protecting our motors, epoxy paint is the go-to option. This specialised paint finish is known for its thickness and resistance, making it ideal for withstanding challenging conditions. In particular, epoxy paint excels in saline atmospheres where it effectively shields against salt-induced erosion. Additionally, it is also suitable for use in environments prone to chemical erosion.
What does C3 mean?
C3 represents the clearance tolerance between the outer race of the bearing and the internal of the bearing housing. Our motor bearings are all manufactured with a C3 tolerance. However, if you need different tolerances, we can accommodate your request.
What is the difference between 1024PPR Encoders and 2048PPR Encoders?
PPR stands for pulses per revolution so a 1024 pulses 1024 times per revolution and a 2048PPR 2048 times. The software controlling the encoder will depend which option you require.
What does an anti-condensation heater do?
An anti-condensation heater is used in motors that will work in cold environments, to stop the motor from condensating when it is turned off. The heater enables the winding to cool down slowly rather than going from very hot to very cold, meaning that condensation risk is eliminated.
What is the normal ambient temperature for motors?
-20°C to +40°C is the design ambient for all of our motor ranges. For any requirements outside of this range, please contact the sales team who will be able to advise the best possible solution.
What is tropicalisation?
Tropicalisation is a process where an anti-tracking varnish is sprayed onto the windings to prevent winding ingress and fungi growth when the motor is installed in tropical conditions.
What are the 2 blue cables in the connection block on 3 phase motors?
They are PTC thermistors that give a resistance value to show whether the motor winding is running within its temperature limits or overtemperature. They need to be connected to a PTC thermistor relay and the thermistors themselves do not disconnect the supply, they are only for measurement. At normal temperature, they will output 250 ohms and when the rated temperature has been exceeded, they will output over 2000 ohms
My single phase motor is running hot, why is this?
Single phase motors generally operate with a case temperature of around 60-70°C. For anything over this it could be either underload or overload. Underloading is a problem on single phase motors as the motor will always pull close to full load current and any excess energy is dissipated as heat causing excessive case temperatures. TEC recommend that the closest possible single phase motor is selected for the application requirements. Another solution to this for motors 1.5kw or smaller is to use a 1ph-3ph inverter and a 3ph motor, for more details please contact the sales team.
Whenis forced ventilation required and what is the benefit?
A force vent fan is a fan that should be supplied with a constant 230/1/50 or 400/3/50 supply depending on the type fitted. They are normally fitted to motors that are run on an inverter below 25hz or above 75hz. The advantage is that the fan is constant running so even when the motor is run slowly, it can still be cooled by the force vent fan.