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Anonymous Poster

problem

06/14/2008 7:34 AM

hi all

there is 3hp motor 460v 3phase, driven by 2.2kw 380/460v 3phase power inverter, the speed referance is potentiometer 10kohm.

when i turn the rheostat the motor run for 5sec then stop and the inverter display showing code means that load current exceeds the limit, actually i tested the output current from the inverter it is about 8.5amps. the inverter input current is 2.3amps

i migger the motor it is ok, the risistance of the three coils are the same 7ohm and tried it on three phase 60hz it is ok pulling about 1amp.

when i turn the rheostat even little,the motor turn and the inverter display shows 9hz output frequency and when i turn rheostat up or down it does not change the speed of the motor still 9hz until it shutoff showing over current.

also when the motor is running i hear acoustic noise like the rotor is touching the stater but when i tried it on three phase supply 60hz it is running fine with out noise, i opened the motor and found it ok, bearings ok.

now i disconnected the motor from the inverter and tried the inverter with out load, it seams to be ok, when i turn the rheostat the frequency goes from zero to maximum 100hz and the opposite.

what do you think is the problem? is it inverter problem or the motor need to be replaced?

please advice

thanks
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YWROADRUNNER
Guru

Join Date: Dec 2007
Location: Cypress Calif
Posts: 741
Good Answers: 23
#1

Re: problem

06/14/2008 8:33 AM

Hello Guest:

If you can supply the make of the VFD, I may have a manual lying around here for it. My best guess here is.

1. The VFD parameters need to be set. If you scroll through the menu in the VFD control panel you should be able to locate the high limit menu. Set the high limit to the full load amps on the nameplate of your motor.

2. If you cannot correct the problem by resetting the parameters in the VFD, the VFD itself is probably the problem. Your testing of the motor would seem to indicate the problem is located within the VFD, either in incorrect parameter setting, or defective VFD.

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Anonymous Poster
#4
In reply to #1

Re: problem

06/29/2008 5:03 AM

hi my friend

the vfd is CEGELEC, the drive number is#VF4006B

THANKS
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ashelec
Active Contributor

Join Date: Jan 2007
Location: Bangalore,karnataka, India
Posts: 24
#2

Re: problem

06/14/2008 11:06 PM

This happens quite often in some VFD drives.Our experience shows that it is primarily the wrong parameter setting or the algorithm in the VFD which does not permit customised V/F setings. Kindly confirm specifications of your motor & VFD to solve your problem.
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Nagarajan.Suresh
Associate

Join Date: Jun 2008
Location: Chennai
Posts: 31
#3

Re: problem

06/16/2008 4:43 AM

Hi,

What I understand is that why the power output becomes reverse when you cahnge the frequeny. Your 50/60 Hz frequency is cycles/secs. It will from 0 to maximum then to zero and neg. maximum to zero and so on. This will be having the impact of turning on/off the Semiconductor equipment used in the inverter.

N.Suresh

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 N.Suresh
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Lspraba
Commentator

Join Date: Sep 2008
Location: India
Posts: 91
Good Answers: 6
#5
In reply to #3

Re: problem

12/12/2008 9:48 AM

This might be the problem of the pot (rheostat)
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Anonymous Poster (1); ashelec (1); Lspraba (1); Nagarajan.Suresh (1); YWROADRUNNER (1)

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