Johnson Controls Penn VFD68D Series Technical Bulletin page 63

Table 46: Stall Prevention (Overvoltage)
Operation oL
Panel
Indication
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 The deceleration time may change. Increase the deceleration time using Pr. 8.
Action
Table 47: PU Stop
Operation PS
Panel
Indication
Description
Stop with
Check Point
Check for a stop made by pressing
Corrective
Turn the start signal OFF and release with
Action
Table 48: Electronic Thermal Relay Function Pre-Alarm
Operation TH
Panel
Indication
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 • Reduce the load and frequency of operation.
Action • Set an appropriate value in P. 9.
Table 49: Undervoltage
Operation UV
Panel
Indication
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 Check the power supply system equipment, such as a power supply.
Action
of the PU is set in P. 75.
of the operation panel.
VFD68 Variable Frequency Drives
63
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