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Old 04-13-2013, 09:27 PM   #21
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Quote:
Originally Posted by tates1882 View Post
A Mis alignment when mounting the motor can produce ol fault. Also a restriction in the chiller plate could be the problem. Is it a plate exchanger or a tank chilling system?
A restriction in a chiller plate would have the same effect as closing the discharge valve
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Old 04-13-2013, 09:29 PM   #22
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Quote:
Originally Posted by sparky970

A restriction in a chiller plate would have the same effect as closing the discharge valve
Which in his case would cause the overload fault. The op has stated it's not a centrifugal pump.
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Old 04-13-2013, 09:32 PM   #23
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Quote:
Originally Posted by micromind

2HP, 5 amps; it's either 208 or 240 3.

I'd also be willing to bet that all 3 phases are seeing overcurrent.

I agree with the others, it's not a motor issue, most likely mechanical.

If the impeller is connected directly to the shaft, it's most likely a centrifugal pump. Is the motor actually a C face or is it a J frame? Like 56J.

As noted, if it is indeed a centrifugal pump, restricting the discharge will lower the current. If it's just about any other type, restricting the discharge will cause the current to rise.

Are the suction and discharge pressures the same on both pumps? If so, look at mechanical issues. If not, then look at fluid issues.
I come up with 6.8 amps.
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Old 04-13-2013, 10:03 PM   #24
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Quote:
Originally Posted by tates1882 View Post
I come up with 6.8 amps.
The values stated in the tables in article 430 are the highest one would expect to ever see, not the typical nameplate values.

A 2HP 3 motor operating on 230 volts will draw somewhere around 5 - 6 amps. A 3HP would be more like 8 - 9, and a 1.5HP would be around 3 - 4.

Of course, exceptions abound, but based on my experience with motors, I guessed 2HP.
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Old 04-13-2013, 10:33 PM   #25
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Originally Posted by xsryman View Post
Speed regulation is needed to get the best cooling as the milk comes from the receiver tank and passes through the chiller. Its not a centrifugal pump so there are no bearings to wear. It has an impeller directly on the motor shaft. It can run across the line but it is not ideal. Only for bypass situations. There is another set up identical to this one right next to it that is pulling the proper amp draw. There is just something about this setup. Checked for phase imbalances at the I/p and o/p. Everything checks out. Just high amp draw at the output.
How hard is it to swap motors with the other identical unit?

I have a feeling it's a pump problem, swapping the other working motor in would tell you for sure.
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Old 04-13-2013, 10:35 PM   #26
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I'm going to stick with the OP's info and agree that there is no external pump bearing. I do believe that a centrifugal pump has an efficiency curve to it but I'm doing my taxes right now so I'm not going to search for the info at the moment. Depending on the system design, the motor current may increase when the flow is limited but then go lower when there is too much of a restriction.

A Captain Obvious suggestion....also make sure the pump is rotating in the right direction.
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Old 04-14-2013, 02:39 AM   #27
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My guess, assuming no other mechanical issues like bearings etc., would be that the old AC Tech drive had a programmed maximum speed below full speed that prevented the motor from overloading. Then when run in bypass, that restriction was removed so it ran full speed and overloaded. When the new drive was put in, you didn't notice the maximum speed restriction that was in the old VFD programming and allowed it to continue to run full speed. Just turn the speed down until the motor current matches the FLA, then set that speed as the maximum speed.
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Old 03-02-2015, 12:06 AM   #28
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Could have used a EPM Programmer to copy data from the old drive.
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Old 03-02-2015, 12:13 AM   #29
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No need to revive a two-year old thread.
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