Installation manual

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Epsilon EP-B Base Drive Reference Manual
Motor Direction Polarity
The direction that the motor turns with a positive command can be changed with the Positive Direction parameter in
PowerTools Pro. The positive direction by default causes the motor to turn CW as viewed looking at the shaft.
CW and CCW rotation is determined by viewing the motor from the shaft end.
Figure 22: Motor Rotation
Positive direction is defined as the command which causes the internal position counter to count "Up". They are:
• A positive analog velocity or torque command (i.e., a higher voltage on the (+) differential input than on the
(-) input).
• A positive direction (+) pulse command.
• A positive preset velocity or torque command.
Encoder Output Scaling
This feature allows you to change the drive encoder output resolution in increments of one line per revolution up to the
density of the encoder in the motor. If the Encoder Output Scaling parameter is set to a value higher than the motor
encoder density, the drive encoder output density will equal that of the motor encoder. Select the Encoder Output
Scaling Enable check box to enable this feature in PowerTools Pro.
You can setup this feature from the Setup view in PowerTools Pro or using the MODBUS® parameters, Encoder Output
Scaling and Encoder Output Scaling Enable.
Current Foldback
Current foldback is used to protect the motor and drive from overload. There are two levels of current foldback: RMS
Foldback and Stall Foldback. RMS and Stall Foldback are displayed on the diagnostic display as a "C" and "c"
respectively.
RMS Foldback
RMS foldback protects the motor and drive from overheating. The RMS Foldback parameter models the thermal heating
and cooling of the drive and motor based on the commanded current and the motor velocity. On power-up, the RMS
Foldback level is zero and is continually updated. When the RMS Foldback level reaches 100 percent, current foldback
is activated and the Foldback Active output function is active.
Each drive is designed to deliver up to 300 percent of the motor’s continuous torque or up to 200 percent of drive rated
current for no less the two seconds when running at 100 RPM or more. If only 150 percent of continuous torque is
required, several seconds of operation before RMS foldback is typical.
During current foldback the Torque Command Actual will be limited to 80 percent continuous motor torque. Current
foldback is cancelled when the RMS Foldback level falls below 70 percent. This could take several seconds or several
minutes depending on the load.
The RMS Foldback value is dependent on both torque and velocity. At low speeds (<20 percent of maximum motor
speed) the RMS Foldback will closely follow the Torque Command Actual. At high speeds (>50 percent of maximum
motor speed) the RMS Foldback will read higher than the Torque Command Actual.
The time constant for RMS Foldback is 10 seconds. This means that if the load is 150 percent of continuous, it will take
about 10 seconds to reach the foldback trip point.