Digital Operator Display
Minor Fault Name
Motor thermostat wiring is faulty (PTC
input).
Repair the PTC input wiring.
There is a fault on the machine side (e.g.,
the machine is locked up).
• Check the status of the machine.
• Remove the cause of the fault.
Motor has overheated.
• Check the load size, accel/decel times, and cycle times.
• Decrease the load.
• Increase accel and decel times (C1-01 to C1-04).
• Adjust the preset V/f pattern (E1-04 through E1-10). This involves reducing E1-08 and E1-10.
Note:
Refrain from lowering E1-08 and E1-10 excessively to prevent a reduction in load tolerance
at low speeds.
• Check the motor-rated current.
• Enter motor-rated current on motor nameplate (E2-01).
• Ensure the motor cooling system is operating normally.
• Repair or replace the motor cooling system.
Digital Operator Display
Fault Name
oH4
Motor Overheat Fault (PTC Input)
• The motor overheat signal to analog input terminal A1, A2, or A3 exceeded the fault detection level.
• Detection requires setting multi-function analog inputs H3-02, H3-10, or H3-06 to E.
Cause
Possible Solution
Motor has overheated
• Check the size of the load, the accel/decel times, and the cycle times.
• Decrease the load.
• Increase the acceleration and deceleration times (C1-01 through C1-04).
• Adjust the preset V/f pattern (E1-04 through E1-10) by reducing E1-08 and E1-10.
• Do not set E1-08 and E1-10 too low. This reduces load tolerance at low speeds.
• Check the motor rated current.
• Enter the motor rated current to parameter E2-01 as indicated on the motor nameplate.
• Ensure the motor cooling system is operating normally.
• Repair or replace the motor cooling system.
Digital Operator Display
Minor Fault Name
ov
DC Bus Overvoltage
The DC bus voltage exceeded the trip point.
• For 200 V class drives: approximately 410 V
• For 400 V class drives: approximately 820 V (740 V when E1-01 is less than 400)
• For 600 V class drives: approximately 1040 V
Cause
Possible Solutions
Surge voltage present in the drive input
power.
• Install a DC link choke or an AC reactor.
• Voltage surge can result from a thyristor convertor and a phase advancing capacitor operating on the same
drive input power system.
The motor is short-circuited.
• Check the motor power cable, relay terminals and motor terminal box for short circuits.
• Correct grounding shorts and turn the power back on.
Ground current has overcharged the main
circuit capacitors via the drive input power.
Noise interference causes the drive to
operate incorrectly.
• Review possible solutions for handling noise interference.
• Review section on handling noise interference and check control circuit lines, main circuit lines and ground
wiring.
• If the magnetic contactor is identified as a source of noise, install a surge protector to the MC coil.
Set number of fault restarts (L5-01) to a value other than 0.
Digital Operator Display
Minor Fault Name
PASS
MEMOBUS/Modbus Comm. Test Mode Complete
Cause
Possible Solutions
MEMOBUS/Modbus test has finished
normally.
This verifies that the test was successful.
6.5 Alarm Detection
316
YASKAWA SIEP YAIP1U 01C AC Drive - P1000 Technical Manual
