Editing Determining motor pole count
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+ | [[File:Wyedelta.jpg|thumb|3 phase AC/BLDC motor winding schemes. A, B and C represent the phase wires coming out of motor.]] | ||
If magnetic pole count of permanent magnet AC/BLDC motor is unknown, there is an easy way to determine it experimentally. | If magnetic pole count of permanent magnet AC/BLDC motor is unknown, there is an easy way to determine it experimentally. | ||
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Procedure: | Procedure: | ||
− | #Disconnect feedback device cable from drive | + | #Disconnect feedback device cable from drive |
#Set drive in torque control mode and enable it | #Set drive in torque control mode and enable it | ||
− | #Manually set torque setpoint | + | #Manually set torque setpoint to produce some noticeable torque on motor (motor not rotate but will start holding position when current is increased). Typically 10-30% of motor rated torque is sufficient. |
#Rotate motor shaft by hand or tool and count the distinct snapping positions per one revolution. | #Rotate motor shaft by hand or tool and count the distinct snapping positions per one revolution. | ||
#Motor pole count is twice as much as the number of snapping positions found in the previous step. I.e. if motor snaps 2 times per revolution, it means that motor has 4 magnetic poles. | #Motor pole count is twice as much as the number of snapping positions found in the previous step. I.e. if motor snaps 2 times per revolution, it means that motor has 4 magnetic poles. | ||
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==Method 2== | ==Method 2== | ||
− | + | Needed items: | |
#3 phase AC/BLDC motors | #3 phase AC/BLDC motors | ||
#Adjustable lab DC power supply | #Adjustable lab DC power supply | ||
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#Motor pole count is twice as much as the number of snapping positions found in the previous step. I.e. if motor snaps 2 times per revolution, it means that motor has 4 magnetic poles. | #Motor pole count is twice as much as the number of snapping positions found in the previous step. I.e. if motor snaps 2 times per revolution, it means that motor has 4 magnetic poles. | ||
− | + | Tips: | |
*If motor is too stiff to rotate, reduce current. | *If motor is too stiff to rotate, reduce current. | ||
*If snaps can't be felt, increase current to make them stronger. | *If snaps can't be felt, increase current to make them stronger. | ||
*If motor has internal brake, it must be electrically opened before the test. Usually such brakes open with 24VDC voltage to brake wires. Check motor specifications first, or use lower starting voltage if unknown. | *If motor has internal brake, it must be electrically opened before the test. Usually such brakes open with 24VDC voltage to brake wires. Check motor specifications first, or use lower starting voltage if unknown. | ||
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