VFD does not show display or Keypad is not Glowing/turning on.
When you give supply to AC drives and display doesn’t turn on you can do the following process to troubleshoot VFD issues. It does matter which drive you have checking process is almost same. (allen Bradley, ABB, Danfoss, Delta, CG, Hitachi, Fuji or any other brand)
- Check Input Supply Voltage. Check whether you have given correct power suppy to drive as per Drive rating.
- If supply is ok. Check DC Bus voltage( Use DC voltage Max on Multimeter to Measure). It Should be approximately 1.5times of Input AC voltage. If this ok means your drives Input circuit or Rectifier circuit is OK.
- If your DC bus voltage is showing Ok than you can Check Control Supply Voltage i.e. 24VDC of Drive. Easiest way is to check cooling Fan. If Cooling fan is working properly means your Drives SMPS is working and you are getting Control Supply Voltage.
- Another way to check Control voltage is to check at control Terminal. You will find one terminal which gives 24 volts as output. (there are different names for different Brands of Drives You can check for manuals or ASK us). If it shows 24Volts means it is confirm that SMPS is working and control Voltage is ok.
- Further check whether Keypad Is connected Properly. If the not Please reconnect it. If Problem doesn’t resolves. Changes the Keypad with another one to Test. (you can use other VFD Keypad to test but that drive should be of Same Make/Brand and same series.)
- If another Keypad is working means there is issue with original Keypad/Operating Display. If that too doesn’t work means you are having problem with Connector of Keypad on Control circuit borad.
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