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5. Calibration
5.1
CALIBRATION PREPARATION
To check the torque calibration accuracy, it is necessary to apply a precisely known torque value. The
most accurate method to apply a known torque is with the use of a beam and weight system. Various
sizes of torque calibration beams and precision calibration weights are available from Magtrol.
The pin location on the torque beam precisely fixes the distance. Therefore, the force (weight)
required will be equal to the torque value divided by the distance on the beam.
5.2
CALIBRATION PROCEDURE
1. Apply full torque to the dynamometer, until the shaft is restrained from rotating.
2. Install the calibration beam on the dynamometer shaft as shown in the following diagram.
Lock the beam with the locking screw against the flat on the shaft. Do not hang the weight
until instructed to do so in step 4.
With the Base Plate
and the Beam level -
Dial Reading - D x W
LEVEL
LEVEL
W
D
TORQUE
Figure 5–1 Calibration Setup
Note:
The calibration beam must be maintained exactly level at all
times.
3. Using lightweight (but strong) line, form a loop and attach it to the weight.
Note:
Do not use a wire hook. Hooks will generally apply the force slightly
off the center line of the pin.
4. Suspend a known weight, at a known distance, from the beam. See
Section 5.1 – Calibration
Preparation
.
5. While preventing the beam from rotating, and maintaining it in a level position, lift the
weight-dial assembly until a balance is attained between the assembly and the beam.
6. Observe the deviation, if any.
7. Remove the calibration beam.
The dynamometer is calibrated and ready for motor testing.