R&M Materials Handling VARIABLE SPEED CONTROLS ControlMaster NXT Service Manual - Manual (Page 46)

R&M Materials Handling, Inc.
4501 Gateway Boulevard
Springfield, Ohio 45502
P.: (937) 328-5100
FAX: (937) 325-5319
46/53 R&M Materials Handling, Inc. reserves the right to alter or amend the above information without notice.
9 TROUBLESHOOTING
The purpose of troubleshooting is primarily to determine whether problems are caused by the frequency converter
or external devices. It is also possible that a faulty external device has caused damage to the frequency converter.
In that case it is very important to repair or change any faulty devices to prevent recurring problems.
Note: When replacing a frequency converter with a new one, the parameter list of the old frequency converter is needed for
copying parameter settings to the new frequency converter.
Note: Reducing of the ramp time from the value of the original delivery is not allowed.
9.1 Problems and solutions
Problem Suggested solution
The frequency converter does not
start (green LED stays off) when it is
started. Check the main voltage between terminals L1, L2 and L3.
Check that there are no devices causing disturbances connected in the same voltage supply
as the crane. These are e.g. devices that require large currents: big motors, welding devices
etc.
NOTE: When the EMC-screw is connected, the frequency converter has RC-filters connected
to the power supply side to reduce disturbances to the network. The capacitors of these filters
may cause the RCD (Residual Current Device) to trip. Therefore, the use of RCD with the
frequency converter controlled cranes is not recommended.
The green LED is continuously on or
flashing (after previous fault) and the
red LED is off, but motor does not run. Check the motor cable connection.
Check the limit switches.
Check the voltage in direction command terminal 1 (DI1) and terminal 2 (DI2). Also common
(terminal 7).
The motor runs poorly: trolley/bridge
doesn’t move as it supposed to move. Check that the load is not over nominal.
Check that all cables are correctly connected and not loose.
Check that all motor parameters are correctly set.
Check that the U/f-curve parameters (switch group S6) are correctly set.
Check the voltage of the slowdown limit switch input (DI4) and limit operation parameters
(switch groups S4-2 and S5).
Check that the motor’s brake opens completely.
Check that the minimum speed parameter value (switch group S2) has not been set too low.
Drive with the device a couple of times the trolley/crane track from end to end to flatten the
runway(s).
Check the parameter settings for current limit (S7).