Technical data
Manual – Gear Units and Gearmotors
141
7
WPU smooth multi-speed unit (→ GM)
Project Planning for AC Motors
7.19 WPU smooth multi-speed unit (→ GM)
Normal mulit-speed motors cannot switch from high to low speed without jerks unless
special measures are taken. In order to limit the occurring regenerative braking torque,
either the voltage is reduced to a lower value at the moment of changeover through
chokes, a transformer or dropping resistors, or only 2-phase switchover takes place. All
mentioned measures involve additional installation effort and switchgear. A time relay
causes the voltage to return to normal voltage conditions. The relay is adjustable. The
WPU unit operates purely electronically.
Function The changeover command blocks a phase of the mains voltage using a triac and in this
way reduces the shifting down torque to about a third. As soon as the synchronous
speed of the high-pole winding is reached, the third phase is activated again in a current
optimized manner.
Advantages of
WPU
• Load independent and wear-free
• No energy loss which means high efficiency
• No restriction on start-up and rated torque and no restriction on the motor starting
frequency
• Minimum wiring
• Suitable for any standard motor
Technical data
GM
03100AXX
Figure 78: Smooth pole-change unit WPU
Type WPU 1001 WPU 1003 WPU 1010 WPU 2030
Part number 825 742 6 825 743 4 825 744 2 825 745 0
For multi-speed motors with rated
current at low speed I
N
in S1 continuous running duty
0.2 ... 1 A
AC
1 ... 3 A
AC
3 ... 10 A
AC
10 ... 30 A
AC
For mulit-speed motors with rated
current at low speed I
N
in S3 intermittent periodic duty 40/60% cdf
0.2 ... 1 A
AC
1 ... 5 A
AC
3 ... 15 A
AC
10 ... 50 A
AC
Rated supply voltage U
supply
2 × 150...500 V
AC
Supply frequency f
supply
50/60 Hz
Rated current in S1 continuous running
duty I
N
1 A
AC
3 A
AC
10 A
AC
30 A
AC
Ambient temperature ϑ
Umg
-15 ... +45°C
Enclosure IP20
Weight 0.66 lb 0.66 lb 1.32 lb 3.31 lb
Mechanical design
DIN rail housing with
screw connections
Control cabinet
rear panel