RO electricity requirement's?

[Bucket Head]

I know very little about RO's and was wondering what kind of power is needed to run them.

Do they require 110 or 220 volt's? Or do the smaller one's use 110 and the large one's need 220?

Just wondering. Thank's.

Steve

[royalmaple]

I don't know about the home systems but the maple ones are 220v, and 30amp circuit + depending on size.

[Russell Lampron]

My Lapierre 150gph RO is 220v and 30 amps. I believe the 600gph RO that Lapierre makes uses the same.

Russ

[Brent]

If you have limited power, like from a generator, you can reduce the start load by putting an inverter on the motor to make it a variable speed control. With the inverter, the startup speed can be programmed to be something like 5 seconds and the inrush current will be way below the full load current. Normally the inrush ( starting ) current is up about 3 x the full load current.

Also you can use a 3 phase motor on the RO which is a bit more efficient than a single phase. Feed 220/1/60 into the inverter and it will put out 220/3/variable frequency.

The other benefit is that you can use the inverter to control the pressure on the RO instead of using a dump valve, which wastes energy in a big way.

We use hundreds of these a year on the machine tools we build.
www.hhrobertsmachinery.com (http://www.hhrobertsmachinery.com)

Not a cheap solution, but it might help, especially if the motor gets up to 5 Hp or so.

By the way the experimental unit I am going to start to put together on Monday will have a pump with a pressure sensor that regulates the pump speed to give me the pressure I want. My system only needs a maximum on the membrane of 80 PSI while I think yours will need a few hundred PSI

[maplecrest]

brent, interesting. i have been working on this power thing for two weeks. i just bought a new r/o 7.5 hp 1200 gallon unit. needs 136 amps to start on a 60 amp breaker. i am putting in a new 200 amp service to the sugar house and at same time want to put in a generator with auto tranfer switch big enough to run the system. the sticky part with the gen is the start amps. so 136 divided by 3 is 45 amps my operating load. correct? how do you figure hp to load amps? i have a 3hp blower on my steamaway, 1/3 hp filter press, two oil guns, 5 hp vac pump, lights ect. how would you figure the load amps needed for a generator?

[Brent]

A real answer would take some work. You would need to know the motor speeds and the inertia loads on each when they start. The inverters we use for machine tools are pretty expensive because they do a lot of tricks that you wouldn't necessarily need in a sugar shack.

You should be OK with your 200 amp service on the whole lot, but running off a generator could be a different issue.

With an inverter you can start at almost any load you want and bring them up to speed over a pretty wide range of time setting, most will go to 30 seconds at least. with this kind of setting, you would never exceed you max full load current by more than 5% or so. I will allow you to get a much smaller generator and use a lot less fuel, but inverters are a bit pricey. If you think you'll be running on the generator a lot, the fuel savings by optimizing the genset size could be substantial. If you just want it for "in case" situations, get a bigger genset and forget the inverters.

If you want to go the inverter route, we might be able to help you.

[Mike]

I have a 600 gal hr Lapierre RO....I have a 15,000 watt generator....Runs the whols sugar house with plenty of juice left.......RO,Filter press,lights,TV,Toaster,coffee maker and evaporator....I use a 2500 watt honda if im not using the RO.....

[maplwrks]

Jeff,
I work for the power co. in your area. You should be able to ask your field tech ( Pete Smith? ) what your total draw will be. I'm sure he may have already figured it. If he hasn't he may be able to help you out right over the phone.

[Brent]

I think you've got yourself on the wrong side of the curve for the generator

RO 7 1/2 hp on 230 volt takes 40 amps full load
Blower 5 Hp on 230V takes 30.8 amps
Steamaway 3 Hp on 230V takes 18.7 amps

And this makes no allowance for startup inrush.

Plus small stuff. Your 15000 watt genset outputs only about 65 amps of 230.
And you need to discover if that is the momentary rating or continuous.

You can't get there from here.

There's no problem on the 200 Amp 220V utility service.


You're going to have to leave something out of the loop when you're on the generator. Maybe run the RO at night to a storage tank then shut it down and run everything else while you boil.

You could split the power for the lights and filter and other small stuff to the smaller genset.

OR
$$$$$ for a bigger genset. Very roughly an upgrade to a 20,000 to 25,000 watt contiuous rated unit seems to be needed, and for some overhead for the start up I'd lean towards 25.

Get all this checked by someone that deals in generators, but I think this estimate is pretty close.

I don't see a problem on your 200 Amp utility service

[maplecrest]

signed contract with pete smith for 200 amp upgrade. was fishing for gen size because i am putting in a generator with this service. last season had no power for a week. went from 140 gallons of syrup a day to 0. figured i lost 14000 dollars in that outage in bulk syrup price. not going to happen again. looking at 25 kw or 35 kw both 1800 rpm but big difference in fuel

[Brent]

from the little I know about diesels, under full load you will get some saving.
but the difference in consumption when running, for example at 1/2 load, is quite substantial.

But, how many hours a year ??? Would you ever save the extra cost for the diesel? I doubt it. But check it out and do the math.

[Mike]

I have no problem with my generator....The RO is the only thing on 220.....Takes around 7000 watts.......Leaves 8000 to run the rest.......It likes gas, around 2-3 gals an HR......But its a 30 hp motor.....Generac brand.....electric start.....

[Brent]

something doesn't add up here.

I think you said the RO was 7 1/2 Hp.

A standard 7 1/2 Hp motor draws 40 amps full load at 230 Volts
40 x 230 is 8000 watts.

And I'm still concerned if your 15000 watt rating in momentary or continuous.
Most makers of generators rate them for peak output and the genset will only put that out for a few seconds to start a motor. If that is how yours is rated you may find it's continuous rating is only 11000 or 12000.
You need to check that. It's a "must know" in your situation.

[Russell Lampron]

Brent,

Mike has the 600 gph RO which is 5hp and the 15000 watt generator.

Jeff is the one with the 7.5hp RO and 200 amp service. Jeff wants to know how big of a generator he needs.

Russ

[Brent]

OK if you're still trying to size the genset, look at the real nameplate ratings on the motors.
208V as compared to 220V is nearly a 10% change in the amps the motors will draw. I was using standardized tables based on 230 V.

And as mentioned above, be very aware of the difference between the full load, continuous rating and peak rate of the genset. It can be a bit of advertising deception. You sure don't want to plunk out all that money and have the lights go out 3 minutes after you turn everything on.

By the way, if it were me, I'd make sure I have one of those power fail battery powered lights on the wall somewhere. If you do blow the fuses on the genset you sure don't want to be stumbling around in total blackness with all the hot stuff in a sugar shack.

Good luck with you hunt.