Motor Protection With Thermistor (Ptc) Acc. To En 60947-8 (Type A Sensors) - ABB UMC22-FBP Technical Description

Universal Motor Controller UMC22-FBP
Software version 4.0
V 6
Chapter 3.6~1

3.6 Motor protection with thermistor (PTC) acc. to EN 60947-8 (type A sensors)

The UMC22 provides terminals T1 and T2 for the connection of positive temperature coeffi cient (PTC type
A sensors) thermistor sensors. PTC sensors are commonly embedded in motor stator windings to monitor
the motor winding temperature.
Since PTC sensors react to actual winding temperature, enhanced motor protection can be provided to
address such conditions as obstructed cooling and high ambient temperatures that cannot be addressed
by the motor model.
Fig. 3-12: UMC22 with connected PTC sensor
When the motor winding temperature reaches the PTC sensor's temperature rating, the PTC sensor's
resistance transitions from a low to high value.
UMC22 is able to perform PTC supervision, with the option of enabling PTC fault trip or PTC fault war-
ning.
Beside that UMC22 detects the following erroneous conditions in relation to the PTC inputs:
- Broken wire: If a connection wire between UMC22 and PTC is broken
- Short circuit: If the input terminals are directly connected
To enable PTC protection do the following steps:
1. Connect the PTC sensor wires to UMC inputs T1 and T2
2. Set parameter 6 (bits 2 and 3) (Bit 1 of parameter 6 is used to set Phase loss protection):
Bits of parameter 6
FieldBusPlug / Issue: 02.2008
u
Motor with intergated
PTC sensors
R
u
0000.0x-- PTC warning / PTC trip
x = 0: PTC warning / x = 1: PTC trip / -: any
0000.0-x- PTC supervision
x = 0: not active / x = 1: active / -: any
0000.0--x Phase loss protection
x = 0: not active / x = 1: active / -: any
- 31 -
T1 T2 3 4
UMC22-FBP