Generator / Transfer switch questions...

[NM_Shooter]

I'm shopping for a generator to put on the work site to power my compressor and miter saw.  I'd also like to use this for short power requirements at the cabin and also at my home.  I'm shopping for a fairly beefy generator, one with 9kW surger.  A couple of questions come to mind:


1)  The ones I am looking at all have 240V outlets, and multiple 120V outlets.  Should I assume that these all put out two phases of power, similar to my home meter base source?

2)  Regarding transfer switches, I'd like to power my entire house from the generator.  But it appears that the transfer switches that I am seeing come with built in circuit breakers.  Does anyone make a "whole house" 200Amp manual switch only?  (3PDT) I'd like to tie in two phases from the genset directly into my existing electrical panels, and then carefully ration power as required throughout the house.  Manual only, as I don't want the switch to cost more than the generator!!!

How is this usually done?  I need to power a well, fridge, freezer, some lights, heater, security system, and misc. outlets around the house (not all at the same time obviously).  I think it would be a serious pain to rewire all of these circuits to take advantage of a transfer switch with built in subpanel.  Help!!!!

Thanks,

-f-

[NM_Shooter]

OK... I've done some more looking around and still not liking my options.  I can't beleive the cost of the manual switches 

Perhaps the cheapest way is to isolate the few circuits that are must haves... that would be:

Well pump (240V, lots of surge current)
boiler and heater pump
kitchen circuit (fridge)
kitchen lights
living room lights

How does an individual circuit transfer switch install?  Do you have to slice open your walls and do a lot of re-routing of wiring?   Any links, photos, offers to come over and install welcome.

-f-

[MountainDon]

Iota makes a few different size switches. I first ran across them when looking for one for the RV. They were very helpful via email. Ask them if their units are UL approved for home use... I can't say for sure. They also have some nice battery chargers.

http://www.iotaengineering.com/its.htm

Using a transfer switch in a residence will require some work, especially if you want to select only certain critical circuits. I'm not certain, but the power company would probably insist on an automatic switch. If a manual switch could be used it must be foolproof to eliminate any possibility of generator power backing into the power grid.

[NM_Shooter]

Thanks Don,

I am now looking at the smaller (read "cheaper") transfer switches, such as the switches made by Reliance.  I am fairly sure that all of the transfer switches that are made whether manual or automatic are all break-before-make style. 

I am trying to understand the terminology of this stuff though... as they say that they are "single phase" yet support 240 V operation.  This embarasses me as I am a EE (in my defense in only do small signal semiconductors!).  I am guessing this is single phase vs. three phase operation... but still confused as I thought that residential homes had two phases... each 180 degrees apart, and that for 240 you used both of these phases. 

Arrrgghhh!  I should have paid better attention in school.

-f-

[glenn kangiser]

For generators, look at Miller welders.  Most come with a 10KW 120 /240 generator and you get the welder with a high  quality engine also.

[MountainDon]

I have to admit to being confused by the "phases" thing. If I stick to 120 VAC or any DC I'm okay. 

I liked the Iota as they were more reasonably priced (when I was looking a few years back) and made in USA to boot. They've been very reliable. MTL there are others that are excellent as well.

Glenns idea re the Miller gen/welder is a good on if you think you'd like a welder. Peter Nap bought a diesel chinese generator a while back.

http://countryplans.com/smf/index.php?topic=3550.0

Maybe he'll read this and add any more recent thoughts or comments?

[Redoverfarm]

NM I operate fairly cheap when I can and it is only temporary. I run a heavy gauge wire from my breaker box (circuit breaker installed) to an outside box. When I am in a power outage I just disconnect the main power in the panel, switch the generator breaker (50 amp)in my panel box and feed the box from there.  I have to be selective and only permit those circuits absolutely needed and intermitent with others as I need.  Then when the power comes back on I reverse the power sequence with the main panel box being the last to be switched to it's normal position.  But as I have said before I do not have codes of compliance.  I strickly adhere to my procedures as not to put any power companies employees at risk.

[NM_Shooter]

I have a lead on the 7kW continuous, 9kW surge, electric start, new in box for $499.  This is a bigger genset than I initially wanted, but can't pass up this price.

I've been talking to some folks at Reliance Controls and they have set me straight...

Residential power is referred to as single phase, even though you have two hot lines that are 180degrees out of phase with one another.  There are two main types of power...single phase, and three phase.  This refers to the arrangement of the power with regards to the neutral and ground.  Three phase is in a "Y" or in a "Delta" configuration, and is only industrial.  

So if you see a "single phase" application, it means the same as your house.....typically two hot lines which can be combined to 240V.  

It appears that the transfer switches are wired in within your circuit breaker box.  You pull the wire from the output of the breaker, and attach the transfer switch to the output of that breaker.  Then a return wire comes from the transfer switch and is attached via wire nut to that house circuit that you just disconnected.  The transfer switch then controls power to that circuit either from the genset or from the house breaker.  

[Willy]

OK here is the skinny on 3 phase and single phase. 3 Phase is for industrial use normaly and single phase is normaly used for residential use. Single phase is 120/240 volts AC and 3 phase is 120/120/208 or 240 volts AC depending on if it is a Delta or WYE System. So the generator you want is a single phase 120/240 volt AC one and Northern Tool sells them on line cheap. You can get a 15 KW gasoline one electric start with all the frills for around $1300.00 and it is a nice one. I just installed one for a guy for back up power. Now Harbor Freight Tools sells a 200 Amp Manual Transfer Switch for around 400.00 but you have to split the incoming power between the meter and main panel. That is not easy to do. You can buy a 6-12 circuit GenTran or Reliance panel that has a plug for your generator to plug into and it taps into your main panel to the circuits you want on back up only. They are easy to hook up, you just hook the 1" FLEX INTO THE HOUSE PANEL THAT HAS THE WIRES FOR THE BREAKERS INSIDE IT. After you hook this flex into the panel you pick the breakers you want to feed and pull the wire out of it put the red one into the breaker and the black one with the same number wire/nutted to the wire you took out of the breaker. That is pretty much it for hooking it up. The hardest part is putting the short flex into the panel and mounting the GenTran Panel next to the main panel. Nice part about this system you can still take the generator to other places and use it. They sell a Complete System at Home Depot for around $2400.00 that is a automatic transfer and automatic start but it is harder to install and should be done by a electrician or at least have one help you. I have done both many times in the past all the way up to 250 KW industrial Generators. I like the simple ones myself cause if you have a problem you can use another generator to run it. Also the auto start ones have a lot of electronics that can mess up on you. Most gentran type switches are only rated for 30 amps 120/240 volts AC and that breaks down to a 7200 Watt Generator but having the extra 15KW one helps in starting bigger motors and runs at about 75% LOAD on a loaded up system of 7200 watts. You do not want to run a generator above 75% very long to keep the windings cool and have it last a long time. Remember that the GenTran Type Systems only have 20 Amp rated switches and you can't run a 30 Amp 240 volt electric water heater with them. You do have a couple 240 volt switches that you can run water pumps ect with. If you don't use them you pull the tie hande between them and use each switch for a 120 volt circuit. This way you can use the 240 vote double switches for 2 single 120 volt circuits. Mark

[glenn kangiser]

Thanks for the info, Mark.  I'm on my home brew solar only so don't get into much of that.  My generator hookups are fairly simple - for charging batteries I just plug in my big inverter charger, but for bulk charging I hook the welding leads to stub wires off the batteries and kick in about 120 amps on constant current.  I have enough batteries to handle this and monitor the volts as a welder doesn't taper, but at this setting the over voltage on the wind generator kicks on to burn off excess power by pumping water using a relay setup I made.  I use normal 240 V 1.5 hp pump so it pulls about 10 amps max. as I recall.  Hope that makes sense.

[Willy]

Thanks for the info, Mark.  I'm on my home brew solar only so don't get into much of that.  My generator hookups are fairly simple - for charging batteries I just plug in my big inverter charger, but for bulk charging I hook the welding leads to stub wires off the batteries and kick in about 120 amps on constant current.  I have enough batteries to handle this and monitor the volts as a welder doesn't taper, but at this setting the over voltage on the wind generator kicks on to burn off excess power by pumping water using a relay setup I made.  I use normal 240 V 1.5 hp pump so it pulls about 10 amps max. as I recall.  Hope that makes sense.

Makes sence to me and I forgot to add one thing about generators when you do not need much power like to watch TV and a few lights on run a real small generator or 12 VDC to 120 VAC Converter set up like you have except smaller in size. That way you will save a lot gasoline. No reason to run a big 7-15KW generator for a few hundred watts of power needed. If you just took a deep cycle rated marine battry and set it up on a converter to 120 volts say a 1500 watt one it will take care of the computer, tv and some lights off extention cords. Just trickel charge the deep cycle battry and maintain the conections to keep them clean. You need to sell set ups like this to people and let them pick up the battry. You could also include a solar charger and it would work for cabins to deal only with lighting ect. I am a caveman and still only have a 35KW and a 6KW for back up and still need to set up my quite one that will give me power with out going outside and starting them up and transfering power. Part I don't like is when it comes back on I have to switch back, shut off the generator and then buy more fuel for them. Mark

[glenn kangiser]

One other thinfg I do is something like you mentioned.  I have a 3000 Watt generator on a small welder - Lincoln Weld and Power.  I fill the tank on it -- it runs about 2 hours with just the inverter charger plugged in.  That inverter matches itself to the generator output.  For some reason the other inverter I have doesn't do that although they are both Trace 4024's.

Anyway, I fill it up - plug in the inverter -- batteries charge until gas runs out -- it is manual start so nothing has to be done until the next time I use it.  Carb is dry so next start is easy - no old gas or other problems.