D311 x-genset questions

1800 rpm genset is an option for the 4V5001-up D311. Requires the 9F8147 governor group, 2H3332 governor spring and a 0.470 inch rack setting for non-parallel operation.

The 1200 rpm setup uses the 5F7930 governor-group, 1H9257 governor spring and 0.475 inch rack setting.

That is flat out for the D311 @ 50.5 hp so the engine needs to be in good shape.

Hi Red,

How much electrical power do you need from the generator?

I would say if you are under 15kW or so then you will not over load the diesel engine at 1800 rpm as 15kW would present only about 20hp load to the engine.

By the way, you can't rewind the 6 pole alternator to a four pole easily. The poles (large) are on the rotor and you have a four pole rotor which would need to be replaced with a 6 pole to utilize 1200 rpm to generate 60Hz. 4 and 6 poles are very different in physical size and mass. The only thing you can easily change by reconfiguration is the output voltage.

I don't see a problem if you only apply modest loads (i.e under 5kw per phase).

Bob

thanks OM....good info....I am just starting in on this project so I will keep you all posted on what happens....

Bobcat....i don't wanna get away from the 1200 rpm.....I have a 6 pole for this machine that needs to be rewound befor use....its 3 phase and I would like to rewind it to single phase as I have no need for 3 phase (portable camp is 120/240).....as far as usage....10kw summer, 15-17kw winter....I am running another D311 reconected now and at times its overloaded, I want to stick with the D311 because its the best set I have found as far as reliability and fuel economy compaired to anything newer...

what is the ratio for HP to kw?....I have never gotten a good answer aside from roughly 2hp/kw, but I am thinking that is a little high HP wise?

hello redcatman,the spec sheet only shows kw for fuel per used ,not per hp ,bruce oz

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[img]http://s315.photobucket.com/albums/ll477/bacoly/foley%202/?action=view¤t=d311elecsetsr-2.jpg[/img]

thanks guys....seems like there are a as many different HP to KW ratios as thereid manufacturers......but it does appear that it is just slightly less than 2hp/kw....like 1.7-1.8 ish

1 hp is 0.746kW

D311 can carry 30hp load continuous at 1200 rpm. The capability goes up to 38hp at 1800rpm

1200 would be 22kW or about 7kW per phase balanced on other words load is appx equal on each phase 1800 rpm would be about 28kW

Any cat gen of this era can make single phase from any two of the three phases but you are limited to 2/3 power or about 14kW or you will overload the generator. Your 17kW load should not overload the engine and only marginally overloads the alternator

Another approach would be to go with 1800 and the 4 pole and get an external transformer to step down to 240/120

This would put you 100 rpm higher than the approved output for the engine but your load of 17kW is a little more than half than the rated load of 38hp at
1700 rpm

Just a thought. Replacing the rotor with a 6 pole may be easily possible. I don't know. I would thnk you would also need the right yen set regulator in addition to the governor mentioned up thread

Good luck

I was just wondering who you found to rewire your generator to single phase as I would like to do the same with the 311 genset I have & I'm only located about 2 hours west of you. Any information would be greatly appreciated.

Your 3 phase generator can supply single phase by using 2 lines and the neutral if it has one. With a neutral from a wye or star connection, this gives you 120/208 (or 127/220,139/240 etc depending on the regulator setting) or 277/480 😮 instead of 120/240. With a 3 lead/delta stator, you have only whatever the line-line voltage is so usually 240 or 480 only.

There are 4 lead delta stators with a neutral that can supply 120/240 single phase and 240 3phase, but I have never seen an old CAT set with this configuration.

As was stated earlier, you are usually still limited to the 3 phase amperage rating, so you wind up with 2/3 of the kVA rating. BUT you will have enough engine to pull that full amperage at any power factor (kW is equal to kVA) so you end up with more than 2/3 of the original kW rating (about 5/6 instead of 4/6).

If you have more than 3 or 4 generator output leads coming from the generator head, you may be able to reconnect for different voltages and single phase etc.

9-10 leads allows high/low 3 phase reconnections
12 leads will allow reconnection to both high and low voltage 3 phase as well as single and 3 phase 120/240.

It can be difficult to make a reconnected set work if it was not designed for reconnection😕 The voltage regulator and exciter must be reconfigured to supply the correct excitation to the field. A set with the separate DC exciter generator like the old CAT sets should not be a problem, but most were not designed to be reconnectable beyond high/low 3 phase.

A stator rewind to single phase should be possible, but most shops probably hesitate to do it in case it doesn't work properly/ratings are invalidated etc. I attempted to get a 3 hp 3 phase motor stator rewound to single phase recently and the shop would not consider it. It's certainly possible, it's just not what they do on a regular basis.

Catcrazy.....I haven't found anyone yet....anything in Grande Prairie is far to expencive so I am looking further south....mine needs a rewind regardless so I am gonna try and find someone that will do it single phase, I know it can be done...and curiously cat shows a part # for a single phase head....they must have been a very rare critter...


when I do find someone Ill be sure to let you know....

oh ya.....every cat genset I have seen of this vintage has been 10 wire, but im sure there are other types out there..

Sean