Teco Installation and Maintenance Manual
TEFC Squirrel Cage Induction Motors
Teco Electric and Machinery Company
Manual Number: IOM ~ TEFC Rev.01
15
3.9.
AUXILIARY DEVICES
3.9.1. Please refer to your specification and the motor nameplate to determine if
the motor is fitted with thermal winding protection devices.
The following are the most common:
One set (one per phase – total 3 off) of PTC winding thermistors.
Two sets (two per phase – total 6 off) of PTC winding thermistors.
One set (one per phase – total 3 off) of PT100 winding Resistance
Temperature Detectors (RTD’s).
Two sets (two per phase – total 6 off) of PT100 winding Resistance
Temperature Detectors (RTD’s).
3.9.2.
Where specified motors may also be equipped with PT100 bearing
Resistance Temperature Detectors (RTD’s).
3.9.3.
Thermistors are positive temperature coefficient type (1000 ohm @ tripping
temperature) refer to specification table for tripping temperature.
They are a tripping device only and not a temperature detector.
Thermistor leads should be connected to an appropriate thermistor control
relay from a reputable supplier.
3.9.4.
RTD’s where fitted are of the platinum type (PT100) with a reference
temperature of 0°C at 100
.
RTD leads should be connected to an appropriate motor protection system
from a reputable supplier.
Recommended temperature settings for RTD’s are as per table 2 below.
DEVICE
TYPE
LOCATION
ALARM TRIP
RTD
PLATINIUM 100
@ 0
O
C
WINDING
140
0
C
150
0
C
RTD
PLATINIUM 100
@ 0
O
C
DE & NDE BEARING
90
0
C
95
0
C
Table 2