FAQ

USEFUL INFORMATION ABOUT SYNCHRONOUS MOTORS

What is the difference between synchronous and asynchronous motors?

In contrast to asynchronous motors, synchronous motors have rotors with permanent magnets. This results in different characteristics:
> more efficiency
> constant speed (independent of load fluctuation)
> extremely short start-up and stopping times
> self-holding torque in powerless state

For which nominal voltages can you supply motors?

Basically, windings for all voltages between 12 V~ and 3×500 V~ are available. Windings for 230 V~, 115 V~, 24 V~, 3×400 V~ and 3×230 V (frequency inverter type) are standard.

Do I need a brake?

The use of powerful permanent magnets means that synchronous motors possess self-holding torque in powerless state. This means that our motors are not subject to switch off delay, which makes them perfect for reversing operations. If the application requires higher self-holding torque, our 4-pole motors from the ROBASE range are an excellent choice.

Does short-time blocking cause damage to motors?

Short-time blocking of the drive does not cause thermal damage to the winding. You should still attempt to avoid blocking to avoid damage to the gearbox.

How are your motors protected against dust and water?

The DIN VDE 0530, EN 60529, Part 5 standard defines protection classes for housings (this does not apply to the output shaft) for rotating field electrical devices. The protection class is indicated by the IP tag and two numbers. Our drives are compliant to IP40 by default. The terminal box version is optionally available to IP55 protection standard.

When do I need a capacitor?

Capacitors are only needed for alternating current motors. The winding is split into the main and auxiliary phases. The main phase is directly connected to the mains power supply. In contrast to this, a capacitor is located downstream from the auxiliary phase to achieve the required phase shift and thus build up a rotating field. Three phase motors do not need a capacitor.

How can I change the drive speed?

The speed of a synchronous drive depends entirely on the mains frequency and does not depend on the load or voltage. Frequency converters allow ROBASE motors to be run at between 7 and 70 Hz (ROSYNC and ROSLYDE: 1-70 Hz). We recommend ROSYNC, ROSLYDE and 6-pole ROBASE motors for use with frequency converters.

Which operation types are possible with your motors?

Our motors are designed for continuous operations by default. The winding can be reinforced to provide more output power. At the same time, this reduces the permissible duty time. We provide windings for S2 and S3 operations. Always keep to the duty time indicated on the type plate. Failure to do so will cause overheating and thus permanently damage the drive. Additionally you can get the motors with built-in thermal protection switch.

Can drives be run at high and/or low ambient temperatures?

Our drives are designed for ambient temperatures between -25°C and +50°C, planetary gears for -10°C through +50°C. Please consult us for temperatures outside these ranges.

Is it a problem if the drive becomes hot during operations?

Our motors are designed to insulation class F for a maximum winding temperature of 155°C at a max. environmental temperature of 50°C. The surface temperature of the drive can be hot for longer periods of operations without causing damage to the drive. The wire we use for the windings is designed to resist temperatures of up to 180°C.

CAUTION: Do not exceed the specified duty times with motors designed for short duty cycle!

Can all synchronous motors be run as stepper motors?

Our synchronous motors can be run as stepper motors assuming modified inductor controls. Our 6-pole motors are best suited due to their favourable resonance characteristic.