Rectivar drop voltage when connecting to motor
Rectivar drop voltage when connecting to motor
(OP)
I have this situation:
Dc motor is not running continuously, it only run one quarter at a time.
When I remove the motor and check the voltage of my Dc drives (Rectivar), i was getting 480vdc into A1-A2 terminal and 240volts into F1-F2 terminal. when i connect the motor again and start, i can get only 8vdc into A1-A2 and 240vdc into F1-F2. The supply voltage is correct which is 415 vac. Is it the motor or the drives is faulty?
Dc motor is not running continuously, it only run one quarter at a time.
When I remove the motor and check the voltage of my Dc drives (Rectivar), i was getting 480vdc into A1-A2 terminal and 240volts into F1-F2 terminal. when i connect the motor again and start, i can get only 8vdc into A1-A2 and 240vdc into F1-F2. The supply voltage is correct which is 415 vac. Is it the motor or the drives is faulty?





RE: Rectivar drop voltage when connecting to motor
Check that excitation current is there. Use a DC clamp to measure current. Voltage alone will not tell the truth.
If no excitation current, check field winding resistance.
If excitation is there and armature current is nominal, then the motor is most likely mechanically blocked.
More details would help solving your problem. For instance: Is this a new drive that never has run before? Or is it an old one that just stopped working?
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Rectivar drop voltage when connecting to motor
RE: Rectivar drop voltage when connecting to motor
When you say "it only run one quarter at a time", does that mean a 90 mech degree turn and then stop?
Or is it something else you describe?
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Rectivar drop voltage when connecting to motor
RE: Rectivar drop voltage when connecting to motor
RE: Rectivar drop voltage when connecting to motor
RE: Rectivar drop voltage when connecting to motor
In the latter case, it is probably only the fact that you are running the motor without load and haven't tuned the speed control properly.
What happens when you turn up the speed reference? What happens when you brake the shaft? When you say that current is between 7.5 and 8 amps - does that mean that the current stays between those values continuously? Or that it hits those values when motor is rotating? Or at standstill?
We are trying to help you, but you do not give us much information. The excitation current is something you still haven't told us. Nor the nameplate data.
What does the commutator look like? Do you have any sparking?
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Rectivar drop voltage when connecting to motor