GENERATOR, NOW WHAT ?

I found a diesel air cooled generator on ebay, it's a 12kw , I won the bid and will pick up soon. Now I am thinking about an automatic transfer switch. Do you have to isolate independent circuts or can they transfer to all circuts in the breaker box ? I have 200 amp service and the generator is rated for 42 amp ( probably under rated ) I was told they use communication wire to start the gen.,this one has manual start and would be good to have a oil pan heater for winter. Are they really worth the price ? I see they can start the gen. once/week, once/2 weeks that seems like a good thing. Are they reliable (lightning strike, power surge, computer malfunction, etc. etc. ) ? I realize I can't bull the 200 amps out of the thing but my average daily use is 42 KWH (NOW I AM NOT USEING MY HEAT PUMP ,MET-ED HAS ENOUGH OF MY $$$ FROM THAT !!! ) ANY THOUGHTS GOOD OR BAD.

Yes, a Auto or Manual transfer type Switch box is a must to isolate the generator from the main power or certain circuits, so it doesn't feed back to the line and hurt a line worker.

I only have 6 circuit Transfer switch with a 30 amp plug outside that I plug my portable generator into. then flip the switches, plug it in and fire it up. Enough for heat and some lights, fridge, etc...thats all we need.

There are many different types of transfer switches, I saw one that hooks right up to your meter box and isolates the feed coming in.

The best solution is a whole house transfer switch. It will transfer the source of power from your utility company to your generator. By it's very nature it isolates the lines and no generator power will back feed to the utility company wires. It's available in manual or automatic models. It needs to be rated the same or greater than the service it feeds. In your case 200 amp. It will be expensive, often a significant percentage of a generator's cost. There are alternates.

One is to re-wire selected circuits in your home to a smaller distribution panel. Then this smaller distribution panel has the transfer switch, manual or automatic. It's lower cost because the switchgear rating can now be reduced to the rating of the generator. Selecting what circuits to re-wire and actually doing it are often difficult. Usually the existing wires are two short. Lengthening them in a way that meets electrical code is possible but needs space and is labor intensive.

A second method is to back feed the generator. This is possible and still meet the electrical code. It depends on a mechanical lock out of your existing main distribution panel circuit breaker with the backfeed switch or breaker from your generator. The objective is to prevent any possible generator power from being fed back to the utility companies wires. This can be accomplished with products like the Kirk key. See:

http://www.kirkkey.com/default.aspx?Page=Products

You will have to engineer the lock out system to your needs. The basic idea is to use electric Solenoid Controlled Interlocks to prevent the house main circuit breaker switch from being on whenever the generator is running. Download:

http://www.kirkkey.com/default.aspx?Pag ... %20Schemes

and look at scheme 35A. Systems using the Kirk Key are commonplace in industrial switchgear.

My guess the backfeed method with Kirk Key lockout will be the least expensive. Of course it's a manual only transfer method.

My 15 KW water cooled diesel generator has a 1 KW electric coolant heater. I normally turn it on only when I'm expecting bad weather. For other times I added a glow plug controller. I don't regularly start my generator for testing purposes. The starting battery is continuously charged with a high end microprocessor controlled battery charger. The fuel needs anti-bacterial treatment.

Do the automatic transfer switches need a battery to perform the switch when the power goes out ?

I believe the automatic uses relays, that are energized from the line power, if the power goes out, they switch (off) to the other set of contacts automatically.

info
http://www.generatorjoe.net/html/whataboutsws.html

http://www.electricgeneratorsdirect.com ... itches.php

AA130FIREMAN wrote:Do the automatic transfer switches need a battery to perform the switch when the power goes out ?

It uses utility company power all the time to hold the contactor in the "use utility power" position. Then when utility power fails the spring force in the contactor transfers the connection and starts the generator. There are some timing circuits involved. The transfer switch that came with my generator powers these timing circuits from the generator starting battery. It's not a trivial design problem, because you don't want to start the generator under load, but yet you want power transfer ASAP.

One critical system I was involved with had a three phase electric motor driving a three phase generator with a huge flywheel. The entire 50 KW load could coast for a few ten's of seconds until the backup generator could be automatically brought online. It also had utility company feed from two completely independent directions. In the twenty years I knew of the system we never lost utility power from both sources at the same time.

I have a 6 circuit manual transfer switch. I have to go down there after I hook up & start the gen outside & manually throw all 6 to GEN from LINE. I wish it had just 2 more circuits so I can run the lights in the bathroom, & power the washing machine, but that's only needed if we lose power for several days or more ... not a common thing. All the circuits are wired in series. I can shut the power off right now to any one of those circuits using the transfer switch. The best part of having the switch is the 2 watt gauges. You can monitor the balance between 120V legs, & calculate your system usage.

SMITTY wrote:I have a 6 circuit manual transfer switch.

Smitty, I have the same setup, but I have 16 circuits. A sub-panel with a 60amp main C.B. being fed by the main panel, and a second 60amp C.B. fed by the Gen. These two C.B's are inline with each other, with a strap between them, so only one can be switched on at a time. Either "Main" C.B. is on, or the "GEN" C.B. is on. They feed the sub-panel, and thus the 16 house circuits I moved here from the main panel.
Are your 6 circuits using 1 inch C.Bs? You can probably double the number of circuits if you use 1/2 inch C.Bs. 240v C.Bs also come in 1/2 inch format, but they will be in a block of 4 C.B.s, either 2 240v circuits, or 4 120v circuits.

Ahh ... I see how you did it. Nice setup!

I have a commercially manufactured setup. Was here when I moved in. I like your setup better ... then I could just add circuits as needed. With the one I have, I'm sort of stuck with what I've got ... unless I can it & buy a new panel. I could probably double up some of the lighter loads, but that;s probably not the best way to go about it. Safer to just toss an extension cord out the bathroom window & plug it into the gen.

Note the hot water furnace label ... I'm shopping for a warm air boiler.

SMITTY wrote:I have a 6 circuit manual transfer switch. I have to go down there after I hook up & start the gen outside & manually throw all 6 to GEN from LINE. I wish it had just 2 more circuits so I can run the lights in the bathroom, & power the washing machine, but that's only needed if we lose power for several days or more ... not a common thing. All the circuits are wired in series. I can shut the power off right now to any one of those circuits using the transfer switch. The best part of having the switch is the 2 watt gauges. You can monitor the balance between 120V legs, & calculate your system usage.

If yours is like mine (a GenTran 5000W transfer switch), you can get "half" breakers and install two 15A circuits in a single slot. I did that for the same reason - I needed an extra circuit. I made sure the original circuit was also only 15A first because most of the house is 20A circuits.

Chris

Ooops, never mind, SMITTY, didn't see your picture until after I posted.....here's what I have: http://www.gen-tran.com/eshop/10Expand.asp?ProductCode=200660.

Yep, Heres my panel. Its a Gentran 7500. I hard-wired 2/3 romax into it, which is buried in a 4" conduit between the house and the barn. The Gen stays in the barn.

Now as far as the automatic transfer swicth, I like the idea but, this generator has a pre heater that you have to hold a switch for(as it stated, 1 minute) and then hit the start button. I started it cold at 50 deg. and tried 30 seconds, had to hit it again so it would start. Do they have a switching gear to take care of the preheat cycle before start on a diesel, this unit also has an oil pan heater, guess that would solve this but I don't want to use excessive electric . Also, do the start switches use oil pressure to keep the starter motor going till it is running ?

what kind of unit/engine is it. since its air cooled ya cant use a coolant heater.. usually they use the voltage signal from the charging system to complete any run cycle or theres a rpm sensor that completes after "greater than crank" speed. there are quick-heat glow plugs and old school slow heat ones. maybe check with the manfacturer or repair/parts for upgrade???

That heater should come on as soon as the gen is "on" & ready to start. Must be an older style system? Never saw one where you had to hold a button in. I'm sure that could be wired to come on automatically fairly easily ... like something similar to automotive designs.

It's a june 1993 built unit in an outdoor inclosure. The cabinet says to hold the preheat for 1 minute before starting. I tried 1/2 minute when the outdoor temp. was 50 and she tried, but would not stay running. 1 minute does the trick. Guess I should post some pictures of the BEAST. Next I would like to find a 138 gallon fuel tank.