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Cause
Possible Solutions
Insufficient voltage insulation between motor phases.
When the motor is connected to terminals U/T1, V/T2, and W/T3, voltage surges occur
between the motor coils and drive switching.
Normally, surges can reach up to three times the drive input power supply voltage (600 V for
200 V class, and 1200 V for 400 V class).
• Use a motor with voltage tolerance higher than the max voltage surge.
• Use a motor designed to work specifically with a drive when using a 400 V class unit.
• Install an AC reactor on the output side of the drive.
The motor fan has stopped or is clogged.
Check the motor fan.
n
Drive Does Not Allow Selection of Rotational Auto-Tuning
Cause
Possible Solutions
The drive is in the incorrect motor
control method for Rotational
Auto-Tuning.
• Check if the drive is set to V/f Control by accident (A1-02 = 0).
• Change the motor control method to Open Loop Vector Control (A1-02 = “2”).
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Motor Hunting Occurs at Low Speeds
Cause
Possible Solutions
Excessive load inertia in Open Loop Vector Control.
• Excess load inertia can cause motor hunting in Open Loop Vector Control due to slow motor
response.
• Increase the speed feedback detection control time constant (n2-02) from its default value
of 50 ms to an appropriate level between 200 and 1000 ms. Adjust this setting in combination
with n2-03 (Feedback Detection Control Time Constant 2).
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Overvoltage Occurs When Running at a Constant Speed
Cause
Possible Solutions
Excessive load inertia in Open Loop Vector Control.
• Loads with a lot of inertia (fans, etc.) can trigger an overvoltage fault when operating in
Open Loop Vector Control.
• Switch to the V/f motor control method.
• Adjust the values set for the speed feedback detection control time constant (n2-02, n2-03).
n
Motor Stalls During Acceleration or With Large Loads
Cause
Possible Solutions
Load is too heavy.
Take the following steps to resolve the problem:
• Reduce the load.
• Increase the acceleration time.
• Increase motor capacity.
• Although the drive has a Stall Prevention function and a Torque Compensation Limit
function, accelerating too quickly or trying to drive an excessively large load can exceed
the capabilities of the motor.
n
Motor Will Not Accelerate or the Acceleration Time is Too Long
Cause
Possible Solutions
Frequency reference is too low.
• Check the maximum output frequency (E1-04).
• Increase E1-04 if it is set too low.
Check U1-01 for proper frequency reference.
Check if a frequency reference signal switch has been set to one of the multi-function input terminals.
Check for low gain level set to terminals A1 or A2 (H3-03, H3-11).
Load is too heavy.
• Reduce the load so that the output current remains within the motor-rated current.
• In extruder and mixer applications, the load will sometimes increase as the temperature drops.
Check if the mechanical brake is fully releasing as it should.
The torque limit function is
operating in Open Loop Vector
Control.
• Check the torque limit setting. It may be too low. (L7-01 through L7-04).
• Reset the torque limit to its default value (200%).
Acceleration time has been set too
long.
Check if the acceleration time parameters have been set too long (C1-01, -03, -05, -07).
Motor characteristics and drive
parameter settings are
incompatible with one another in
V/f Control.
• Set the correct V/f pattern so that it matches the characteristics of the motor being used.
• Check E1-03 (V/f Pattern Selection).
The right combination of motor
characteristics have not been set
in Open Loop Vector Control.
Execute Rotational Auto-Tuning.
Incorrect frequency reference
setting.
• Check the multi-function analog input settings.
• Check if multi-function analog input terminal A1 or A2 is set for frequency gain (H3-02 or H3-10 = “1”). If so,
the frequency reference will be 0 if there is no voltage (current) input provided.
• Ensure H3-02 and H3-10 are set to the proper values.
• Ensure the analog input value is set to the right value (U1-13, U1-14).
The Stall Prevention level during
acceleration and deceleration set
too low.
• Check the Stall Prevention level during acceleration (L3-02).
• If L3-02 is set too low, acceleration will take a fair amount of time.
• Increase L3-02.
6.9 Troubleshooting without Fault Display
SIEP C710606 20 OYMC AC Drive - V1000 User Manual
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6
Troubleshooting
7/16/2008-13:23