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Speed goes up and down with a rhythm...
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This phenomenon of motor speed
going up and down in a noticeable rhythm is called “hunting”. Hunting, or speed of motor going
up and down in rhythm, can be caused because of following reasons : - Load on the motor too small
and the adjustments done at normal load do not hold good for light loads. - Current feedback absent. Check
the signal on Burden Resistor of Current Transformers, with an oscilloscope. - Gain of the speed amplifier
does not match with the mechanical inertia. Normally too much gain causes this
type of hunting. - Too much of Integral time. Irregular speed variation can be
caused by loose coupling of tachogenerator, unstable output of RAMP
generator, dry solder in feedback path of tachogenerator signal etc. |
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Speed control not satisfactory
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