Siemens Energy & Automation, Inc.
38
Table 8 Troubleshooting - Continued
Trouble Cause Check/Remedy
Motor branch circuit Branch circuit protective Size the device in accordance with all applicable codes
protection trips during device incorrectly sized (NEC/CEC).
starting or running
Check circuit breaker trip settings.
Incorrect power wiring Check all power wiring connections to determine if a phase-to-
causing a short on phase or phase-to-ground short is present.
input or load side of
controller
9.3 Inside Delta Wiring Problems
Figure 23 shows a correct inside delta connection. With the cor-
rect connection, the motor runs properly with current limit dur-
ing starting and the line and leg currents are balanced.
Table 9 lists four improper connection problems and the unsuc-
cessful response for each. The “Example” column illustrates
only one of many combinations that may be responsible for the
problem.
Table 9 Inside Delta Wiring Problems
Problem Response/Example
1. Reversed Winding The motor runs but makes non-
normal sounds and the running cur-
rent is very high.
2. Dead Ended Winding The controller trips out on a single
phase fault. The line with the Dead
End Winding will have no current
flow. The other two lines will have
very large currents flowing.
Note: Repeated attempts at start-
ing with this connection can dam-
age the controller.
3. Dead Ended on The motor does not start. There is
All Windings no current flow on any of the lines.
The controller indicators LED 1 and
LED 2 come on at the same time
when a run command is given.
4. Starter to Fault The motor runs but there is no cur
Contactor rent limiting during starting. The
Lead Swaps line and leg currents are balanced.
Due to the phase shift in the leg
currents compared to the con
troller’s internal timing for starting
control, there is no current limiting
during starting.
Figure 23 - Proper Inside Delta Wiring Connection
Table 9
Problem 1 Problem 2 Problem 3 Problem 4
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