
Rockwell Automation Publication 20P-TG002B-EN-P - February 2018
37
Component Test Procedures
Chapter 2
Thermistors and Thermal
Switches
Motor overheating is detected by an external, user-supplied thermistor (PTC)
or thermal switch connected to terminals 78 and 79 on the control power
terminal block on the lower, right corner of the pulse transformer circuit
board. See
for terminal block location.
Motor overheating is typically identified by a “Motor Over Temp” fault (F16).
See “Fault Descriptions” in Chapter 4 of the PowerFlex Digital DC Drive User
Manual, publication
for a
circuit diagram.
• If a thermal switch is used, a 1 kΩ resistor must be placed in series
between the switch and either terminal 78 or 79.
• If neither a thermistor (PTC) or a thermal switch is installed, a 1 kΩ
resistor must be connected between terminals 78 and 79.
The drive heatsink temperature is monitored by a bimetal thermostat
connected directly to the heatsink. When the heatsink temperature is too high,
a “Heatsink OvrTemp” fault (F8) occurs. See “Fault Descriptions” in Chapter 4
of the PowerFlex Digital DC Drive User Manual, publication
for
details. See
on page
for a circuit diagram.
During normal operation, 1.6V DC is present between terminal 78 and drive
common. When an open circuit exists between terminals 78 and 79, 24V DC
will be present at terminal 78 to drive common. If the 24V is missing, the pulse
transformer board may need replacement.
Relay Outputs
Terminals 35 and 36 and 75 and 76 are N.O. relay outputs. The relay output
between terminals 35 and 36 is configured with parameter 1392 [Relay Out 1
Sel]. The relay output between terminals 75 and 76 is configured with
parameter 629 [Relay Out 2 Sel]. See “Using Contactors” in Chapter 1 of the
PowerFlex Digital DC Drive User Manual, publication
, for more
information.
The “Main Contactor” fault (F10) indicates a problems related to a contactor
used with the drive. See “Fault Descriptions” in Chapter 4 of the PowerFlex
Digital DC Drive User Manual, publication
for details.