Startomatic regulation/governing ?

[millman56]

Hi,
can anyone help me out with a Startomatic problem please ?    When setting up a 220 volt 4.25 Kva (unity pf) Lister VA Startomatic set, initial settings, alternator 233 volts @ 1523 Rpm no load,   2200 Watt resistive load applied, 204 volts @ 1475 Rpm. This seems to be very poor regulation compared to a 240 volt 4.5 Kva  (unity pf) 8-1 set with a "Fatboy alternator"  which only dropped 4 volts with the same 2200 Watt load.    As I am not a regular Startomatic user and what I need to know is do the non fatboy alternators have poor regulation or do I have a fault. The engine governor linkage appears to be fine as switching the load in and out gives identical results every time.  The way I set it was Rpm firstly then voltage via the shunt resistor.   

Thanks in anticipation,   Mark.

[Chris R]

Hi Mark,

My experince with the two Generator versions "fat boy" and "thin man" is about 20 plus years ago, so take what I have to offer as coming from a grey brain.
I am not a schooled electrical engineer, but I have been #$%$ around with these generators since I was 15 now 61.
"Thin man" has two adjustable resistors. The first resistor, which as I recall, is located in the dog house and adjusts the no load voltage. I think the input may have come from the start circuit windings and is DC current from the generator and feed back to the field windings. The output load runs through a transformer and the secondary is rectified by an old fashioned bridge rectifier and feed back to the same field or another field. I am not sure, it's been a long time ago. There is the second adjustable resistor that is bolted to the frame of the generator below the transformer. This is used to adjust the load voltage. I can't remember if this resistor is located before or after the bridge rectifier.
I would check to insure that the bridge rectifier is working and also the the connections to the adjustable resistor are good and clean and also that the wire on the adustable resistor has not broken or burnt through somewhere. These resistors get good and hot. Also check the brushes on the commutator (Not the slip ring brushes). They should be checked as well, but I don't think that is causing the voltage drop that you are having.
Best of luck,
Chris R

[millman56]

Hi Chris,  you were spot on with your advice to check the bridge rectifier, as soon as I removed the cover it was plain to see that the bracket had dropped off at one end allowing vibration to break 2 solder connections.  Once this had been repaired the SOM was put on a load test, the outcome of which I noted,    no load, 231 volts @ 1535 Rpm,  2200 Watt load 224 volts @ 1479 Rpm,  4400 Watt load 215 volts @ 1438 Rpm.   This would appear a satisfactory output for the SOM, what do you think?

Many thanks,

Mark.

[Chris R]

Mark,
Glad to be of help. You might be able to do a little better with adjusting the resistor below the transformer, but be careful. The slide clamp has been known to break. It can get retty damn hot an brittle. If you want to adjust it, soak the clamp bolt over night with liquid wrench type stuff and go easy on lossening it up. Here in the Bahamas we have a lot of corrosion to deal with and rushing things usually leads to broken bolts etc. Better to put some oil on it and than go have a rum drink or two and relax. Deal with it the next day and you will save time in the end.

Best regards
Chris R

[millman56]

Hi Chris,   have got its regulation nearer the "fat boy`s"  and it will do for me fine.      It must be great hearing  the warm breeze in the palm trees, watching the blue Caribbean lapping on the shore and sipping rum whilst letting things free off.     Here I`m chillin out by freezing my nuts off, drinking gallons of tea and gripping hot exhausts in an effort to regain some sensation in my fingertips, ah well only  3 months of this till the rainy season starts ( UK summer).

Kind regards,

Mark.

[Chris R]

Mark,

Glad to hear you are purring along again.
Weather here right now is ideal.When June comes along I will be sweatng gallons and wondering what in the ^%$ I am doing here in the heat.
I miss my ole Fat Man and skinny boy both powered by Lister VA's. FM and SB went bye bye years ago along with one of the VA's.  Idler bolt came loose, the crank shaft hit it, cracked the engine case. Big mess and in those days I did not know about the "India" connection and deemed the ole girl to a sea burial as not worth fixing due to no parts. It was/is a great boat mooring.
The other Va has been restored to working condition with Lima backend. I added a golf cart starter generator to it about a month ago and now have a SOMOID. Works well, spins her right up with compression off.
She is out back put putting away and powering my house and charging batteries right now. (I live off grid)
Chris R Abaco Bahamas

[potter]

Hi chris on the golf cart starter/gen are you driving from the flywheel using a v belt? I have done this on a small Lister before but never tried on my cs thinking I would not get the r.p.m on the large flywheel.
    Potter

[Chris R]

Potter,
I will check on the size of the pulleys I used.  The V pulley on the golf cart starter was replaced by a used a serpentine pulley off of a bigish alternator found at AID (NAPA store and auto repair center in Marsh Harbour, Abaco, Bahamas). This was so I could match it up to sepentine type pulley/hub (This hub may have been the pulley off car/truck water pump) I had knocking around for years. I mounted it to my the Lima alternator using the taper lock bolts that holds on  the V belt double pulley.
The Golf cart starter had to be out board mounted becuase of the direction it rotates. It is mounted for now on a piece of 3/4 plywood that is tapconed screw to the concrete generator foundation. (The ton of concrete) and sticks out pass the base. This was for testing purposes but works so well that it will say that way for now.
The starter/generator is only used for starting as I still wanted to used my original compression release stop solenoid and don't have enough wires running back to the house to energize de energize the golf cart starter/gen. A trickle charger keeps the battery charged.

So it works like this.
pursh button to energize a start solinoid to  power to the golf cart starter/generator
serpentine belt drive to the sepentine hub bolted to the lima alternator
Double V belt drive to the Lister VA
VA cranks up to starting speed in about 5 seconds and I push down on the compression lever and off she goes. release the start button for the golf cart starter.
It works very well and brings the VA up to speed as well as the old original starter generator that crapped out years ago.
Sometime when I have nothing else to do I will hook up some other relays and time delay switches and make a real sart-o-matic out of the ole girl and start and stop her from the house, if I wanted to.
Chris R

[potter]

Thanks Chris yes if you get a chance I would be curious what the ratios are . Your not using the gen side to keep the start battery charged ?, I found this worked out well on my small Lister.
Thanks
Potter