Inside Delta Wiring Problems - Siemens Sikostart 3RW34 Instruction Manual

Table 8 Troubleshooting - Continued
Trouble Cause Check/Remedy
Motor branch circuit
protection trips during
starting or running

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.
Figure 23 - Proper Inside Delta Wiring Connection
Problem 1
38
Branch circuit protective
device incorrectly sized
Incorrect power wiring
causing a short on
input or load side of
controller
Table 9
Problem 2
Size the device in accordance with all applicable codes
(NEC/CEC).
Check circuit breaker trip settings.
Check all power wiring connections to determine if a phase-to-
phase or phase-to-ground short is present.
Table 9 Inside Delta Wiring Problems
Problem
1. Reversed Winding
2. Dead Ended Winding
3. Dead Ended on
All Windings
4. Starter to Fault
Contactor
Lead Swaps
Problem 3
Siemens Energy & Automation, Inc.
Response/Example
The motor runs but makes non-
normal sounds and the running cur-
rent is very high.
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.
The motor does not start. There is
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.
The motor runs but there is no cur
rent limiting during starting. The
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.
Problem 4