GA 75 starting problems

by Ognjen Dabic
(Srebrenica, Bosnia and Herzegovina)

I would have one question and a request if you could help us .

We have two compressor GA 75 and GA 808 appears to us was a problem starting the compressor GA 75 thereof.
The issue is , at the first point of the compressor comes to his heavy boot. The display does not eject any error later when reached normal operating temperature continues to work .
Do you have any idea what might be in terms of what we could pay attention

Comments for GA 75 starting problems

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Dec 23, 2015
starting
by: Doug in s.d.ca

Is this a GA 75 VSD model? Or just GA 75?

Anyway, a lot got lost in translation.

Is the machine running on the correct frequency of 50 or 60 HZ for your area?

Dec 23, 2015
Please explain more
by: Carl

What do you mean by "to first comes his heavy boot"? What is the problem??

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Set backup GA75+ to start on pressure?

by james
(uk)

Atlas GA75+ information plate

Atlas GA75+ information plate

Hello, I have an Atlas GA75+ that I have set to a timer however I have another machine I wish to run as my main compressor and i'd like to set the atlas to come on if the other one cant cope or cuts out then the Atlas can come on due to pressure drop as a backup unit.

I'm just looking for some help how to set that up?

Thanks

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Jun 09, 2015
set pressures
by: Carl

Hi,
This is a simple process, whatever your main compressor is set to for example lets say your main compressor is set to go "on load" at 7.0 Bar then "off load" at 8.0 Bar, just set the Atlas to go "on load" at 6.5 Bar and "off load" at 7.5 Bar.
This will cause your main compressor to run your system quite happily and your Atlas to sit there on standby. If the demand of air is high and the main compressor cant cope, the pressure drops to 6.5 Bar, the Atlas will start and boost the pressure to keep your system to pressure
Hope that helps

Carl

Jun 08, 2015
automatic backup
by: Doug in s.d.ca

Just connect both to the same line, without check valves.

Set the cut-in for the one you want to run mostly slightly higher than the backup.

If/when the pressure drops below what the main one puts out, the second one will also turn on.

The cut-out pressure can be the same or one or the other can be set to run a bit longer to cut-off.

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GA75VSD motor fluctuations

by Jake
(Waterloo, Ontario, Canada)

Hi, like the title says...however at lower flow rates e.g. 23-40% the machine runs steady, but once we ramp up air usage and the flow rate gets up to 60% the motor starts fluctuating, ramping up, than dropping down, and ramping up again.

It builds pressure up to 121psi than drops down to 118psi than ramps up to 121psi again (i have pressure set at 120psi), all within a few seconds, and it does this all day.

Any ideas what could be the cause of this?
Thanks.

Comments for GA75VSD motor fluctuations

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Jan 30, 2016
Motor
by: Doug in s.d.ca

Interesting.

So in effect, your receiver became too small.

Thanks for the feedback.

Jan 30, 2016
Motor
by: Doug in s.d.ca

Mike:

(and Jake, can you tell us about the demand?)

If this were a mechanical speed control, we'd (me, anyway) say that "it's hunting".

It's not clear what kind of demand this has, but if it's fairly constant, the vsd should find a steady speed to match the demand, right?

So, maybe the question is, is the demand at lower loads constant, but it becomes variable at the higher demands the OP mentions?

Jan 29, 2016
problem solved
by: Jake

Thank you for your responses.

The machine was acting different than it should, it got pressure up to 121psi then backed off(my set point is 120), but the pressure would rapidly drop to 118 so the motor would ramp up again...this cycle took only three seconds at a time, and do it all day long continuously.

I'm talking pass tense because as it turned out, part of the problem was that we had a undersized manual pressure valve after the tank (which I removed) but it didn't completely fix the problem. Later I had a professional come in and they found that one of the line filters was clogged, after he replaced it the machine runs as it should.

Jan 29, 2016
GA75VSD motor fluctuations
by: Mike

It is normal for a variable speed drive compressor to have 'motor fluctuations'

Your compressor is constantly trying to maintain your 120psi setpoint

As plant demand increases so will rpm until it reaches the desired 120psi and rpm backs off to help maintain your constant 120psi, the motor rpm will constantly change to achieve maintaining setpoint

Are you asking this question because the machine is acting differently than usual?

If you contact me directly I can explain things better to you, please send serial number of unit

(Please post responses here as comments so all can share in the advice. Mike, if you have a website, do add the URL to the compressor repair services page for all to access. Thank you. Bill)

Jan 25, 2016
motor
by: Doug in s.d.ca

Could be a software bug, but we'd probably hear more about it if that's the case.

I'm thinking possibly the pressure sensor is a little flaky.

Try changing the setpoint up or down a couple notches and see if it makes any difference other than what you'd expect.

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GA75VSD has 0xfa61 error?

by Melvin gonzales
(Qatar)

Hello good pm.
I am melvin gonzales
Working in qatar.frijns
Structural steel.
Can you give me idea about this kind of error 0xfa61? For GA75VSD model.

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