Warning - PENN Controls - VFD68Bxx - VFD68Cxx - VFD68Dxx - Three‐Phase Motor Speed Controller - VFD68 Three‐Phase Variable Frequency Drive

VFD68 Variable Frequency Drives Technical Bulletin
Product name
VFD68 Three‐Phase Variable Frequency Drive
Document type
Technical Bulletin
Document revision
C
Revision date
2019-08-09
Part number
24-7664-3051

When a warning occurs, the output is not shut off.

Table 1. Stall Prevention (Overcurrent)
Operation Panel Indication OL
Description During acceleration When the output current of the VFD exceeds the stall prevention operation level (P. 22), this function stops the increase in frequency until the overload current decreases to prevent the VFD from resulting in overcurrent trip. When the overload current has reduced below stall prevention operation level, this function increases the frequency again.
During constant-speed operation When the output current of the VFD exceeds the stall prevention operation level (P. 22), this function reduces frequency until the overload current decreases to prevent the VFD from resulting in overcurrent trip. When the overload current has reduced below stall prevention operation level, this function increases the frequency up to the set value.
During deceleration When the output current of the VFD exceeds the stall prevention operation level (P. 22), this function stops the decrease in frequency until the overload current decreases to prevent the VFD from resulting in overcurrent trip. When the overload current has decreased below stall prevention operation level, this function decreases the frequency again.
Check Point
  • Check that the Pr. 0 setting is not too large.
  • Check that the Pr. 7 and Pr. 8 settings are not too small.
  • Check that the load is not too heavy.
  • Check for any failures in peripheral devices.
  • Check that the value of P. 22 is appropriate.
Corrective Action
  • Increase or decrease the Pr. 0 setting by 1% and check the motor status.
  • Set a larger value in Pr. 7 and Pr. 8.
  • Reduce the load weight.
  • Set stall prevention operation current in P. 22 (The default value is 150%.) The acceleration/deceleration time may change. Increase the stall prevention operation level with P. 22.
Table 2. Stall Prevention (Overvoltage)
Operation Panel Indication oL
Description During deceleration, if the regenerative energy of the motor becomes excessive to exceed the regenerative energy consumption capability, this function stops the decrease in frequency to prevent overvoltage trip. As soon as the regenerative energy has reduced, deceleration resumes.
Check Point Check for sudden speed reduction.
Corrective Action The deceleration time may change. Increase the deceleration time using Pr. 8.
Table 3. PU Stop
Operation Panel Indication PS
Description Stop with STOP/RESET of the PU is set in P. 75.
Check Point Check for a stop made by pressing STOP/RESET of the operation panel.
Corrective Action Turn the start signal OFF and release with PU/EXT.
Table 4. Electronic Thermal Relay Function Pre-Alarm
Operation Panel Indication TH
Description Appears if the cumulative value of the P. 9 reaches or exceeds 85% of the preset level. If it reaches 100% of the P. 9 setting, a motor overload trip (E. THM) occurs.
Check Point

  • Check for large load or sudden acceleration.

  • Is the P. 9 setting is appropriate?
Corrective Action

  • Reduce the load and frequency of operation.

  • Set an appropriate value in P. 9.
Table 5. Undervoltage
Operation Panel Indication UV
Description If the power supply voltage of the VFD decreases, the control circuit will not perform normal functions. In addition, the motor torque will be insufficient and/or heat generation may increase. To prevent this, if the power supply voltage decreases below about 115 VAC (about 230 VAC for 400 V class, about 58 VAC for 100 V class), this function stops the VFD output and displays .

An alarm is reset when the voltage returns to normal.
Check Point Check that the power supply voltage is normal.
Corrective Action Check the power supply system equipment, such as a power supply.
Table 6. Safety Stop
Operation Panel Indication SA
Description Appears when the safety stop function is activated (during output shutoff).
Check Point Verify that the jumper wires connect terminals S1, S2, and SC together.
Corrective Action
  • When not using the safety stop function, short across terminals S1 and SC and across S2 and SC with shorting wire for the VFD to run.
  • If SA is indicated when the jumper wires between terminals S1, S2, and SC are connected, then an internal failure might be the cause. Contact PENN by Johnson Controls Application Engineering at 1-414-524-5535 or 1-800-275-5676.