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PF Softstarter F45 Fault (24V Loss)

Problem: What is the cause or source of a 24 Volt Loss F45 fault on a PF Softstarter? How can this fault be cleared? How can it be determined if the issue is with the PF Softstart control module or if other external conditions are causing this fault?

Cause: This fault can be caused by one of the following:

• The PF Softstarter control power source is below the recommended minimum rating
• Power connections on terminals 11, 12, 13 and 14 are not correct or not securely fastened to these terminals
• Back voltage from control relays controlled by the PF Softstarter auxiliary outputs occurs when control relay coils are de-energized
• Internal damage to the PF Softstarter control module

Solutions

The following steps can be taken to correct and clear the fault.

1. Verify that the control power source which powers the PF Softstarter control module is sized at the following:
• 75 VA for 120-240V AC input for PF Softstarter controllers from 5 through 480 amps
• 130 VA for 24 V AC input for PF Softstarter controllers from 5 through 480 amps
• 50 Watt for 24 V DC input for PF Softstarter controllers from 5 through 480 amps
• 800 VA for PF Softstarter controllers from 625 through 1250 amps
2. PF Softstarter Control Power connections are as follows:
• Terminal 11 is 24 V, 120V or 240V AC (hot) or plus 24 V DC depending upon the PF Softstarter control module utilized
• Terminal 12 is the AC neutral or minus 24 V DC source depending upon the PF Softstarter control module utilized
• Terminal 13 contains a jumper between it and terminal 12
• Terminal 14 is connected to control circuit or chassis ground
3. Install surge suppressors on control relay coils being controlled by the PF Softstarter auxiliary outputs.
4. Verify the PF Softstarter control module is not damaged by completing the following checks:
• Remove the control module from the PF Softstarter power structure and do a visual inspection of the printed circuit board to see if there is any damage to board components.
• Check for damage or discoloration to the T2, T3, or T4 components.
  
• With the PF Softstarter control terminal block, measure resistance between terminals 11 and 12. Ensure that no other connections are made to these pins and they are screwed down or an erroneous value will be seen.