Mitsubishi Electric FR-A840-00770 (30K) User Manual (English)

Questions and Answers:

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Jennifer JonesAug 16, 2025
What to do if hunting occurs in Mitsubishi Electric FR-A840-00770 (30K) motor?
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  Nicole CollinsAug 16, 2025
  If hunting (vibration or acoustic noise) occurs in the motor or machine connected to your Mitsubishi Electric Inverter, it might be due to a speed control gain that is too high. Try performing easy gain tuning or setting Pr.820 lower and Pr.821 higher. Alternatively, the torque control gain could be too high. In this case, set Pr.824 Torque control P gain 1 (current loop proportional gain) lower. Finally, incorrect motor wiring can also cause this issue, so ensure that the wiring is correct.
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Paul ReyesAug 23, 2025
What to do if Mitsubishi Electric FR-A840-00770 (30K) speed does not accelerate to the command speed?
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  tamarabarkerAug 23, 2025
  If the speed of your Mitsubishi Electric Inverter does not accelerate to the command speed, it may be due to a torque shortage or the torque limit is operating. To resolve this, try raising the torque limit or increasing the capacity. Also, ensure that you are using PI control instead of only P (proportional) control.
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Amy NewtonAug 27, 2025
Why does Mitsubishi Electric Inverter motor speed fluctuate?
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  Nancy RomeroAug 27, 2025
  If the motor speed connected to your Mitsubishi Electric Inverter fluctuates, it could be due to several reasons. First, verify that the speed command sent from the controller is correct and implement EMC measures, and set Pr.72 lower. Another possible cause is a torque shortage, in which case you should raise the torque limit. If the speed control gain is not suitable for the machine, resulting in resonance, perform easy gain tuning.
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Jennifer McguireAug 31, 2025
Why acceleration/deceleration time different from setting in Mitsubishi Electric FR-A840-00770 (30K) Inverter?
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  Stacy HolmesAug 31, 2025
  If the acceleration or deceleration time of your Mitsubishi Electric Inverter is different from the setting, it could be due to a torque shortage, so try raising the torque limit. Alternatively, the load inertia might be too high, therefore set acceleration/deceleration time suitable for the load.
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gfrazierSep 3, 2025
Why is machine movement unstable with Mitsubishi Electric Inverter?
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  Jason GreenSep 3, 2025
  If the machine movement connected to your Mitsubishi Electric Inverter is unstable, it could be because the speed control gain is not suitable for the machine. Perform easy gain tuning to correct this. It could also be that the response is slow due to the inverter's acceleration/deceleration time setting, so set the optimum acceleration/deceleration time.
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Kristi RobertsSep 7, 2025
How to fix rotation ripple during low-speed operation in Mitsubishi Electric Inverter?
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  Ricky BergSep 7, 2025
  If rotation ripple occurs during the low-speed operation of your Mitsubishi Electric Inverter, it might be due to a high carrier frequency affecting the motor rotation. Try setting Pr.72 lower. Another possible cause is that the speed control gain is too low, so try setting Pr.820 higher.

Mitsubishi Electric FR-A840-00770 (30K) Specifications

General

Model	FR-A840-00770 (30K)
Series	FR-A840
Power Rating	30 kW
Horsepower (HP)	40 HP
Enclosure Rating	IP20
Control Method	Vector control
Frequency Range	0.1 to 400 Hz
Protection Features	Overcurrent, Overvoltage, Undervoltage, Short circuit, Ground fault, overheating
Operating Temperature	-10 to 50 °C
Storage Temperature	-20°C to +65°C
Humidity	95% RH or less (non-condensing)
Altitude	Up to 1000 m
Weight	15 kg
Input Voltage	3-Phase 380-500VAC