2024年3月9日发(作者：本心菱)
Shaft Voltage Tester
Handheld Digital OscilloscopeAEGIS-OSC-9200Shaft Voltage Testing Guide
Examples of Shaft Voltage ReadingsHigh Peak to Peak common mode voltage –Typically 20 to 120 volts peak to peak (10 to 60 volts peak). The
waveform image shows the capacitive coupled common mode voltage
on the shaft of the motor. The “six-step” waveform is the result of the 3
phases of pulses from the VFD. The timing of the pulse width modulation
(PWM) pulses to the motor from the drive determines what the
waveform looks like. Sometimes it will look like a square six-step or square wave is what is seen when there is no bearing
discharge and the peak to peak shaft voltage is at its maximum level.
The voltage level may eventually overcome the dielectric in non-
isolated bearings and begin amplitude EDM discharge pattern –Typically EDM discharges can occur from 20 to 80 volts peak to peak
(10 to 40 volts peak) depending on the motor, the type of bearing, the
age of the bearing, and other factors. The waveform image shows an
increase in voltage on the shaft and then a sharp vertical line indicating
a voltage discharge. This can occur thousands of times in a second,
based on the carrier frequency of the drive. The sharp vertical discharge
at the trailing edge of the voltage is an ultra high frequency dv/dt with
a typical “discharge frequency” of 1 to 125 MHz (based on testing
results in many applications).Reference: NEMA MG1 Section 31.4.4.3Low amplitude voltage discharge pattern –Typically the voltages are 4 to 15 volts peak to peak (2 to 8 volts peak).
The waveform image shows a more continuous discharge pattern with
lower dv/dt frequencies. The lower voltage may be due to greater
current
2024年3月9日发(作者：本心菱)
Shaft Voltage Tester
Handheld Digital OscilloscopeAEGIS-OSC-9200Shaft Voltage Testing Guide
Examples of Shaft Voltage ReadingsHigh Peak to Peak common mode voltage –Typically 20 to 120 volts peak to peak (10 to 60 volts peak). The
waveform image shows the capacitive coupled common mode voltage
on the shaft of the motor. The “six-step” waveform is the result of the 3
phases of pulses from the VFD. The timing of the pulse width modulation
(PWM) pulses to the motor from the drive determines what the
waveform looks like. Sometimes it will look like a square six-step or square wave is what is seen when there is no bearing
discharge and the peak to peak shaft voltage is at its maximum level.
The voltage level may eventually overcome the dielectric in non-
isolated bearings and begin amplitude EDM discharge pattern –Typically EDM discharges can occur from 20 to 80 volts peak to peak
(10 to 40 volts peak) depending on the motor, the type of bearing, the
age of the bearing, and other factors. The waveform image shows an
increase in voltage on the shaft and then a sharp vertical line indicating
a voltage discharge. This can occur thousands of times in a second,
based on the carrier frequency of the drive. The sharp vertical discharge
at the trailing edge of the voltage is an ultra high frequency dv/dt with
a typical “discharge frequency” of 1 to 125 MHz (based on testing
results in many applications).Reference: NEMA MG1 Section 31.4.4.3Low amplitude voltage discharge pattern –Typically the voltages are 4 to 15 volts peak to peak (2 to 8 volts peak).
The waveform image shows a more continuous discharge pattern with
lower dv/dt frequencies. The lower voltage may be due to greater
current