Desperately Seeking Help - Need power boost?

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Old 01-15-15, 11:20 PM
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Desperately Seeking Help - Need power boost?

I have a shop where about 400 feet down the road is the 3 phase main in another building. My shop has a 3 phase panel that the electrician ran single phase from to another panel to feed my 6 ice cream machines. There is 208v to each machine - the machines are 208/230 (30amps) but the issue is that when the compressor kicks on the voltage drops to 198ish and the low voltage swtich shuts the whole machine down. I need something to boost the power or regulate the power to the machines so they stay above 200v and the low voltage switch wont shut them down. Do you have anything like this?
 
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Old 01-16-15, 12:42 AM
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Welcome to the forums.

Bad move on your electricians part. He put all the compressors on one phase.

You need.....
two compressors on phase A & B,
two compressors on phase A & C
two compressors on phase B & C

You need to balance your load on all three phases.
Now your electrician will have to run the correct wiring.
 
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Old 01-16-15, 07:28 AM
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Agreed completely with Pete. The single phase panel should be a three phase panel so the compressor loads can be balanced, UNLESS you have some non-standard three phase configuration in the building we are unaware of.
 
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Old 01-16-15, 07:29 AM
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Even if I turn off all of the machines except one - even one single machine wont run on the power provided (falls below 200v every time) - so it would still be the wiring issue with the 3 phase as you said above.
 
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Old 01-16-15, 07:32 AM
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So that would fix our problem with the voltage not staying above 200v? Someone suggested we buy buck n boost for each machine (we would have to buy 12) is this a solution - we are desperate to open and invested everything in this but this power issue is killing us.
 
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Old 01-16-15, 07:35 AM
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Even with just one machine? Wow! That suggests that either the wires are far too small for the distances involved, or your transformer is already very overloaded. Another possible avenue to explore would be if power factor correction (PFC) is needed somewhere on your site. That requires specialized meters to evaluate so I can't say much more than a qualified commercial electrician would need to investigate.

My first step in diagnosis would be to verify all the wire sizes used, do a quick summary of the load on this service, then to measure what the voltage drop is at each panel in the chain to see if there's an obvious red flag. What other kind(s) of machinery are in use on this service? What is the overall service size?
 
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Old 01-16-15, 07:36 AM
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The machines are all single phase - but our panel was 3 phase so he put in a sub panel just for the machines and is running them off that. He put a 100amp breaker in the 3 phase panel for the sub panel (machines) each machine has 2 - 30 amp breakers in the single phase sub panel.
 
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Old 01-16-15, 07:38 AM
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Wait, 200V? That's only an 8 volt drop from nominal. Is this machine really intended for use on 208V?
 
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Old 01-16-15, 07:45 AM
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In the shop there is one 125amp 3 phase panel - (he put a 100 amp break on it) then the electrician wired in a 125 amp single phase sub panel with 32 spaces. Off this single phase panel he has a fridge/freezer combo, 40 gallon hot water tank and then 6 machines (which each have 2 - 30 amp breakers - one for each side of the machine)
 
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Old 01-16-15, 07:48 AM
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The side of the machines states that they are 208/230v - and there is 208 to the machines (we metered it) but when the 230v compressor kicks on in the machine then the power drops to 198 sometimes a bit lower and then the low voltage safety switch turns the machine off (to protect the motor from running hard at low voltage)
 
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Old 01-16-15, 07:48 AM
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Could you give us the manufacturer/make/model of the ice cream machines or a link to it somewhere online so we can see the exact manufacturer specs?
 
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Old 01-16-15, 07:57 AM
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http://sreweb.com/manual/taylor_manu...54_774_794.pdf

Our machines are 794-27

Maybe get someone to try to disconnect this low voltage switch? We are at a total loss as to what to do.
 
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Old 01-16-15, 07:58 AM
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Something does not sound correct. The feeder sounds too small as well as the slight voltage drop affecting the machines. Eight to ten volts of drop is not that much.
 
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Old 01-16-15, 08:10 AM
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The machines trip when they fall below 200v. Every machines is doing the same thing. Had the machines techs out and they said the voltage was dipping down to low when the compressor comes on and then it trips the low voltage swtich. Thats why we were thinking about somehow taking this protection swtch off? Since the voltage is not crazy low?
 
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Old 01-16-15, 09:47 AM
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Ok, so here's what I found from the manufacturer's spec. Each of the six machines you have requires two 208V circuits. The left circuit has MCA 27A, Max OCPD 35A; the right circuit has MCA 23A, max OCPD 35A.

That means your minimum design load, just for the ice cream machines, is (27A * 6) + (23A * 6) = 300A @ 208V (63kVA). Your 100A electrical panel and wiring is at least three times smaller than the minimum required to operate these machines, and I'm guessing the long distance 500'+ from the service entrance is also major contributing factor to the voltage drop.

Even if you were to completely balance the 125A three phase panel, it could supply at most 45 kVA of power and the ice cream machines require at least 63 kVA. That doesn't even count lighting, HVAC, other general loads, etc.

Bypassing the switch will probably void any warranty on the machine. Running on low voltage over time will damage a motor. We don't know whether the manufacturer was conservative with the 200V limit, but I think it's fair to assume they know what voltage level could damage the machine.

What you really need is a 250A+ three phase service to your shop with upsized wires to accommodate the distance.
 
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Old 01-16-15, 09:55 AM
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I have a shop where about 400 feet down the road is the 3 phase main in another building.
I believe the 400 foot feeder from the main panel is your biggest problem, it wasn't sized for the adding of these recent new loads.
 
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Old 01-16-15, 10:05 AM
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Unhappy

Yes that might be the issue - but I dont know how to fix it - we are hooked into a main panel that is the house panel for a complex. Will we need to run new wire? Trying to find the quickest and most cost effective fix for this huge issue.
 
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Old 01-16-15, 10:22 AM
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Based on the above you need a much larger service to your building. This is going to be new wires and panels from the distribution point in the complex. The service to the complex will need to be surveyed to see if it can accept additional load.
 
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Old 01-16-15, 11:53 AM
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Trying to find the quickest and most cost effective fix for this huge issue.
Find a different building that's better suited to your needs? The required upgrade to this building will be pretty costly if it's even possible.

The only other option I can think of is to work with your ice cream dealer to possibly trade these machines for smaller ones that will be more likely to work, although the voltage drop could still be an issue. You could try to get in touch with their engineering department to see if the 200V limit switch could be safely reduced and only run one or two of the machines at once.
 
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Old 01-16-15, 07:34 PM
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Trying to find the quickest and most cost effective fix for this huge issue.
There is no quick and cheap solution.
 
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Old 01-17-15, 05:20 PM
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The primary need is fatter wires from the main building to your building.

It is possible to boost the voltage to around 240 given machines that are rated for 208 to 240 volts with no required voltage preselection or configuration or changing jumpers. Then they will work while the voltage fluctuates between the two voltages. But you can still have complications such as the voltage still going too low if two machines try to start up at the same time. Also, lights and other smaller appliances will react to the voltage changes whether the lights etc. are wired before the transformer or wired to the transformer output.

For these reasons together with the cost of transformers, transformers are probably not a viable idea.
 
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