Yaskawa VS-626 MC5 - Manual (Page 256)

Troubleshooting
9.2.8 If Motor Deceleration is Slow
- 12
9.2.8 If Motor Deceleration is Slow
J The deceleration time is long even when control resistance is connected.
1. “Stall prevention during deceleration enabled” is set.
D When control resistance is connected, set constant L3-04 (stall prevention selection during deceleration)
to “0” (disabled) or “3” (deceleration stall prevention with braking resistor). When this constant is set to
“1” (enabled, the factory-set default), control resistance is not used.
2. The deceleration time setting is too long.
D Check the deceleration time setting (constants C1-02, C1-04, C1-06, and C1-08).
3. Motor torque is insufficient.
D If the constants are correct and there is no overvoltage fault, then the motor’s power is limited. Consider
increasing the motor capacity.
4. The torque limit has been reached.
D When a torque limit has been set in constants L7-01 to L7-04, no torque will be output beyond that limit.
This can cause the deceleration time to be too long. Check to be sure that the value set for the torque limit
is suitable.
D If the torque limit has been set by multi-function analog inputs H3-05 and H3-09 (set value: 10 to 13),
check to be sure that the analog input value is suitable.
J If the Vertical-axis Load Drops When Brake is Applied
D The sequence is incorrect.
D The Inverter goes into DC injection braking status for 0.5 seconds after deceleration is completed. (This
is the factory-set default.)
D To ensure that the brake holds, set frequency detection 2 (H2-01 = 5) for the multi-function contact output
terminals (9-10) so that the contacts will OPEN when the output frequency is greater than L4-01 (3.0 to
5.0 Hz). (The contacts will close below L4-01.)
D There is hysteresis in frequency detection 2 (L4-02 2.0 Hz) . Change the setting to approximately
0.5 Hz if there are drops during stop. Do not use the “running” signal (H2-01 = 0) for the brake ON/OFF
signal.
9.2.9 If the Motor Overheats
J The load is too big.
D If the motor load is too heavy and the motor is used with the effective torque exceeding the motor’s rated
torque, the motor will overheat. Some motor rating are given for short period performance and are not
continuous ratings. Reduce the load amount by either lightening the load or lengthening the acceleration/
deceleration time. Also consider increasing the motor capacity.
J The ambient temperature is too high.
D The motor rating is determined within a particular ambient operating temperature range. The motor will
burn out if it is run continuously at the rated torque in an environment in which the maximum ambient
operating temperature is exceeded. Lower the motor’s ambient temperature to within the acceptable am-
bient operating temperature range.
J The withstand voltage between the motor phases is insufficient.
D When the motor is connected to the Inverter output, a surge is generated between the Inverter switching
and the motor coil. Normally the maximum surge voltage is three times the Inverter’s input power supply
voltage (i.e., 1,200 V for 400 V class). Be sure to use a motor with a withstand voltage between the motor
phases that is greater than the maximum surge voltage. In particular, when using a 400 V class Inverter,
use a special motor for Inverters.
J Autotuning not performed during vector control.
D Vector control is not effective without autotuning. Perform autotuning for motor unit separately.
9.2.10 If There is Noise When the Inverter is Started or From an AM Radio
D If noise is generated by Inverter switching, implement the following countermeasures:
x Lower the Inverter’s carrier frequency (constant C6-01). This will help to some extent by reducing
the amount of internal switching.
x Install an Input Noise Filter at the Inverter’s power supply input area.
x Install an Output Noise Filter at the Inverter’s power supply output area.
x Use metal tubing. Electric waves can be shielded by metal, so encase the Inverter with metal (steel).
x Ground the Inverter and motor.
x Separate main circuit wiring from control wiring.
9.2.11 If the Ground Fault Interrupter Operates When the Inverter is Run
D The Inverter performs internal switching, so there is a certain amount of leakage current. This may cause
the ground fault interrupter to operate and cut off the power supply. Change to a ground fault interrupter
with a high leakage detection level (i.e., a sensitivity current of 200 mA or greater per Unit, with an oper-
ating time of 0.1 s or more), or one that incorporates high frequency countermeasures (i.e., one designed
9