Interroll Drum motor series i, S, S/A, D
General technical information
Version 4.1 (06/2015) en-US 
Translation of original instruction manual
15
 
PTC
Maximum operating voltage W 25
Thermal time constant s < 10
Resistance at switching temperature + 15 K Ω 1330 ... 4000
+ 5 K Ω 550 ... 1330
Ω 550
- 5 K Ω 250 ... 550
- 20 K Ω < 250
In particular, if the motor does not have an internal thermal winding protection, a suitable 
external thermal control relay/contactor must be connected upstream.
A thermal winding protection does not replace the overcurrent protection. In addition, every 
motor must be connected to a suitable overcurrent protection which is set to the rated motor 
current.
Use of 50-Hz motors on 60-Hz supply system
This option is not available for the D-series.
 
Rated motor voltage: 230/400 V - 3 ph - 50 Hz  
System voltage: 230/400 V - 3 ph - 60 Hz
If a 50-Hz motor is connected to a 60-Hz supply system, the frequency increases and, as a 
result, the speed by 20 %. Since the torque decreases accordingly, the motor output remains 
constant. The voltage-dependent parameters change in the speed range under field control at 
60 Hz according to the following table:
System voltage = rated motor voltage
Power P kW 100 %
Rated speed n
n
1/min 120 %
Rated torque M
n
Nm 83.3 %
Starting torque M
A
Nm 64 %
Pull-up torque M
S
Nm 64 %
Pull-out torque M
K
Nm 64 %
Rated current I
N
A 95 %
Optional version: PTC 
(positive temperature 
coefficient)
Effect of using a motor 
with 50-Hz rated motor 
voltage on a 60-Hz supply 
system