Low output voltage on iS7

Low output voltage on iS7

There may be a few parameter settings that can result in a low output voltage.
  1. First off, verify the motor voltage is set correctly at BAS15. By default the iS7 VFD will reduce output voltage
  2. Check the auto torque boost (ATB) setting at parameter DRV15. This should be set to 'Manual' to get the maximum output voltage.  
  3. Lastly, check ADV87 (OVM Mode). This parameter will decrease output voltage based on output current. Set this to 'Yes' if needed. 
OVM M ode Explained

The OVM function can be applied when a high load present and the input voltage is low. This function is used to increase the output voltage.  By increasing the output voltage, the output current correspondingly will drop in overload conditions.

The output voltage cannot exceed the input voltage by using this function.

To clarify,  the output voltage command is limited to linear so that the current is not distorted according to the output voltage and frequency ratio (V/f).  However, in order to increase the voltage a little higher, the nonlinear section of the OVM (over-modulation) area must be used.

The function that can increase the output using this section is the OVM function. However, if this section is used, distortion of the current waveform may occur.