Master Line Speed Command

Follower (Slave) Speed Percent

  Enter a master speed command in percent, as whole numbers. Maximum speed is 100%.

  Click "Master Line Speed" to enter the command. 

  Enter a follower speed command in percent, as whole numbers.

  Click "Follower Speed Ratio" to enter the command.

The follower in this example, can go from 1% of the master's speed, to equal (100%) of the master's speed.

This system uses a typical speed potentiometer as a "voltage divider" which applies a signal voltage to the master drive, over the complete range of the signal input. For example, 0 to 10VDC is the auto-reference input for the drive. The follower potentiometer, further divides the master input reference voltage. Note that this circuit limits the performance of the follower drive. The follower input speed reference will only equal or be less than, the master speed reference. In this system, a speed sensing feedback circuit provides "closed loop" speed control from the each individual drive. Speed fluctuations of drives are independent and not regulated between drives.

• Using two speed "pots" is simple.

• Troubleshooting two speed pots requires a volt-ohmeter only.

• Speed feedback to individual drives provides better drive motor performance

• Signal isolation may be required, depending on the source of the auto-reference.

• Follower speed reference input can never exceed the master reference signal level.

• Voltage reference can droop over long distances. This requires higher signal source voltage, and trim pots.

• Speed feedback circuits can be a source of variation in a two motor system like this.

• 2 potentiometers

• 1 or 2 operator station enclosures for mounting the pots in

• 2 vsd's

• 2 motors 

• 2 speed sensing devices (encoder is shown). Can be on motors, or other machine shafts.

Easy

Difficult