Procedure for 78D176 PC-Boards
After the dynamometer, readout instrumentation and power
supply are connected:
- Be sure all equipment is set for the correct power line
input voltage as specified on the original order.
- If you are using an alternative option power supply, other
than the Model 5200 or 5210, please refer to that manual
for operational details. The 5200-2, and 5210-2 are covered
in the dynamometer
manual - Chapter 5.
- Turn on the readout and power supply, allow a few moments
for warm-up - longer if the equipment is below room ambience.
You will need some precision weights to do the following calibration
procedure. The pin location precisely fixes the distance on
the torque beam, in either metric or English units. Therefore,
the force (weight size) you require will be equal to the torque
value you want divided by the distance on the beam. Select a
weight heavy enough to apply a torque close to the full scale
rating.
- Install the Calibration Beam on the dynamometer shaft
as shown, only leave the weight off.
- Fashion a loop of light, strong line on the weight. Do
not use a wire hook. Hooks will generally apply the force
slightly off the centerline of the pin.
- Apply full current to the dynamometer brake by turning
the Torque or Current control fully clockwise.
- With the beam exactly horizontal, adjust the ZERO trim
pot so that the torque reading is zero +/- 1 least significant
digit.
- Hang a calibrated weight of sufficient size form the clockwise
pin on the calibration beam (Clockwise position - looking
at the front of the dynamometer). The weight times the distance
calculation should be equal to, or near, the full scale
of the dynamometer.
- Adjust the CW cal trim pot so that the torque reading
equals the weight times the distance.
- Transfer the weight to the CCW pin and level the calibration
beam.
- Adjust the CCW cal trim pot so that the torque reading
equals the weight times the distance.
- Remove the weight from the calibration beam.
- Turn the Torque or Current control counter -clockwise
while pumping the calibration beam CW/CCW. This will ensure
that there are no residual bumps left on the rotor.
- Remove the calibration beam.
Your dynamometer is calibrated, ready for motor testing.
Magtrol Load Cells are temperature compensated, designed
for stability. Therefore this calibration should remain constant
indefinitely. However it's a good idea to re-check calibration,
frequently at first, maintaining a record until you have established
a history. If there appears to be excessive drift contact
Magtrol's Repair and Calibration
Department.
For Calibration Procedures for the 78D055 and 78D160 PC-boards
or contact Magtrol Repair
and Calibration to discuss a PC-board upgrade.
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