Electical help needed. Load stabilizer?

[MillbrookMaple]

I am wondering if there is such a thing as a capacitor unit that would stabilize a large initial start load for an electric motor? Here is my situation: I just upgraded to a 75 CFM Indiana Vacuum oil cooled liquid ring pump. On cold start up it pulsates and starts hard and then once it gets going it runs fine and once it is warm it starts and stops smoothly. Today when I started it the power went off. Not the breaker in electric panel but it blew the cap at the transformer. I had to call the electric company to reset the electric. They said that my service to the building is a 100 amp and that distance to the transformer was really long so I am probably not getting all of that at the site. I talked with the manufacturer and he suggested using lighter oil and a couple of other tweaks to decrease the initial compression on the pump so it would start easier. I am just wondering if there might be something we could put between the breaker and the pump that would help with the initial load on the electric service. They tested it and the motor runs at 50-60 amps 25-30 amps per side when running normally. The manufacturer said that the initial draw could be 3x that on a cold start. So any of you electric gurus out there any ideas?

[maple flats]

How long is your run from the transformer? What gauge wire was used? I can tell you what your loss is with these numbers. That may be the whole problem. You may need a shorter wire run. Can you place the pump near the power source, maybe in a small shed for protection and security? A pipe of proper diameter will be cheaper and easier than new wire.
A second idea, get a battery bank and a good inverter to suppliment the surge, then use the inverter to recharge the bank. I have solar power and am grid tied. An inverter near the load will give far better voltage. Make sure the inverter is grid capable. However, these are not cheap. One of my inverters was $3400.00 and another was $2400. The $3400 is tied to the battery bank, and it is an inverter/charger, able to charge by solar or grid. You do not need solar to make use of it. The surge max on mine 6000 watt continuous/12,000 watts surge at 240. Max surge is 10 seconds. You would use far less time. This in conjunction to the grid will do it, if you can afford it. Place the pump close to power source (near transformer) and pipe the vacuum will be much cheaper, but will require a new meter and pole service there.

[maple flats]

How long is your run from the transformer? What gauge wire was used? I can tell you what your loss is with these numbers. That may be the whole problem. You may need a shorter wire run. Can you place the pump near the power source, maybe in a small shed for protection and security? A pipe of proper diameter will be cheaper and easier than new wire.
A second idea, get a battery bank and a good inverter to suppliment the surge, then use the inverter to recharge the bank. I have solar power and am grid tied. An inverter near the load will give far better voltage. Make sure the inverter is grid capable. However, these are not cheap. One of my inverters was $3400.00 and another was $2400. The $3400 is tied to the battery bank, and it is an inverter/charger, able to charge by solar or grid. You do not need solar to make use of it. The surge max on mine 6000 watt continuous/12,000 watts surge at 240. Max surge is 10 seconds. You would use far less time. This in conjunction to the grid will do it, if you can afford it. Place the pump close to power source (near transformer) and pipe the vacuum will be much cheaper, but will require a new meter and pole service there.

[MillbrookMaple]

The Pump is actually right next to the Electric meter and breaker panel. I'm running about 10 feet of 8/3 to the breaker box. I think that the service wire is only 2 gauge and the run from the transformer at the pole is probably 100-150 feet. There is a pole between the building and the pole with the transformer on it. If I have the electric company upgrade the service to 200amp all I would have to do it buy 20ft of 2-0 service wire and a new panel box. I just thought there might be a lower cost option that might do the trick.

[JoeJ]

Millbrook,
I had the same pulsating problem on my oil cooled vacuum. Then last year, a friend installed 2 new Sihi 10 HP oil cooled vacuum pumps that would not start without blowing the breaker or at best,
pulsating for 3-4 minutes. So he put a small electric heater blowing on the vacuum for 15 or 20 minutes and the pumps started without any hesitation. I tried that last year and the pump started
right up. Now it is part of my pre-turn on the vacuum preparation to put a small electric heater blowing on the vacuum head for at least 15 minutes.

Before I started heating the vacuum head before start up, I even installed low viscosity pump oil, at the recommendation of the pump supplier, to try to help with the start up. Since then, after
finding out about heating the pump head, I have talked to several other sugar makers with oil cooled pumps with the same problem. You would think that someone at the maple supply stores would
have know about this problem and simple solution a long time ago.

Joe

[MillbrookMaple]

Thanks that was the kind of thing I needed. I asked the manufacturer about warming the pump up before trying to start it but he really didn't think that would help. We have an electric heat gun in the shed to make putting the releaser tubes on easier. I'll try blowing that near the pump head next time and see if it helps.

[Scribner's Mountain Maple]

I had problems blowing transformers. I told the power company that I had electric motors for sugaring that would surge. They gave me a bigger transformer and it hasn't blown since. Not sure if that will solve your problem, but is free and may help.

[Springfield Acer]

Many times electrical equipment with heavy starting amp draws are controlled by using a VFD (variable frequency drive) with a soft start feature that limits the inrush at start up. You might want to look into that but they generally are not cheap. If you have no other options though, that might work. If you go down that road and can get a knowledgible person to talk with, make sure that you tell them that this a cold start issue and that the current inrush is sustained for longer than normal inrush. The VFD's ability to soft start can avoid large amp draws that can affect your demand rating if your meter is a demand recording type. Higher demand equals higher cost per KW-HR for all electric consumed.

[Rossell's Sugar Camp]

A capacitor on a single phase motor does not "give extra juice" to the motor like most people think it does. It just knocks the current out of phase on the start winding to get the initial rotation of the motor. A vfd or soft start could help also to slowly ramp up the motor and lower the initial draw.

But your best bet is to upgrade your service, this is coming from an electrical engineering technology major in college!

[maple flats]

Millbrook,
You would think that someone at the maple supply stores would
have know about this problem and simple solution a long time ago.

Joe
It often seems they don't care about such issues. They just want your money, and don't get bothered to advise you on potential problems and remedies!