VYPER
™
VARIABLE SPEED DRIVE
INSTALLATION
100-210 IOM (
JUL
09)
Page 31
Figure 24 - Thermistor Motor Protection Wiring
MOTOR THERMAL PROTECTION OPTIONS
The National Electrical Code (NEC) requires thermal
protection for motors operating with variable-speed drive
systems.
Frick employs two types of thermal protection for motors.
One method uses thermistors, and one method uses RTDs.
Figures 23 and 24 show the wiring schematics for both op-
tions.
Figure 25 - RTD Motor Protection Wiring