Everything you always wanted to know about the EWA 10 – EWA 16 power drives!

1. Self-locking:

In all cases, a distinction is made with self-locking between static and dynamic self-locking. Static self-locking only works when stationary and can be cancelled by shaking or by vibration.

This is why our self-locking drive units always have dynamic self-locking (also called auto-braking). This occurs whenever an operating gear unit comes to a complete stop automatically, for example after the motor has been switched off.

2. Load details and service life:

Our nominal load details are minimum figures, not maximum figures, unlike the practice of many other manufacturers. That means that if we quote a torque rating of ‚250 Nm‘, that means that the drive unit is capable of delivering that level of power throughout its entire service life. This explains why our drive units are renowned for having high reserves of power.

On our in-house test benches, we test our units for ­1000 operating hours at the nominal load quoted in the catalogue, over the specified engagement period. The drive units are designed for endurance loads throughout their 20-year service lives, depending on utilization level (actual torque levels applied), application, peak loads and engagement cycles.

The service life may therefore prove to be much longer for your application, but after this length of operation you should certainly have the condition of your drive unit inspected.

3. Electric motors:

We do not use standard motors. Instead, we only use motors with optimized characteristics curves, and we optimize these for each version and for every variant. They are designed in such a way that voltage fluctuations of approx. +/- 5 % can be contended with, even in the 60-Hz range.

We also use S1 motors, although we stamped S3 on them to indicate their intended engagement period. We do this to prevent misunderstandings, because no self-locking gear unit should ever actually be operated on a continuous basis. The electric motors are adapted to prevent the gear units from being destroyed!

4. Single-phase motors:

Single-phase motors are always wired by ourselves before they leave the factory, and are supplied with a long connection cable. That means that the electric motor is switched off directly by the limit switch. This greatly simplifies assembly and is less expensive, because there is no need for a reversible contactor control system. A test run can be conducted on location using manual push-button TST 10.

Having said that, single-phase motors must not be over-dimensioned. If they are operated at levels well below their nominal load rating, they are prone to heating up more, and this shortens their engagement period. The internal winding protection contact can be routed externally.

5. Special voltages:

For 60 Hz we have always used special motors and do not simply run 50-Hz motors faster. We also always guarantee that the nominal load rating quoted is consistently achievable, i.e. not 20% lower as many manufacturers tend to do. This also applies to the other special voltage ratings. All special motors are optimized and tested before they are used on the test bench.

6. 24 V DC motors:

Power drives EWA 10 and EWA 12 can be supplied with 24 V DC motors. A typical feature of DC motors is that current intake rise sharply as torque levels rise.

You should therefore contact us and request our test protocols and diagrams.

7. Smoke & heat extraction systems:

Natural ventilation systems are often combined with smoke &­ heat extraction systems. With building-specific special constructions, no usability verification can be provided in accordance with DIN EN 121 Part 2.

Here, it is possible to apply for consent in individual cases from the construction authorities. Our drive units have been inspected by the Fraunhofer Institut in respect of ‚usability‘ as defined in DIN 18232. Request the Fraunhofer certificate when needed.

8. A60 option:

This option is suitable for use in outdoor environments because it has stainless steel output shafts and a special grade of thermally resistant oil for low temperatures.