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3KW 120V AC genset-eng 4a32--V.R. # 6110-00-764-7621

wassbiplane

Registered
Don't know how to post a new question--Would like to find a schematic on the voltage regulator on a 3KW 120V AC genset-eng 4a32--V.R. # 6110-00-764-7621--I was testing it-I rev'd it up to about 2800 rpm, voltage was 120, about 3.9 KW output--Freq meter was
not registering (too slow) volt adj rheostat had no effect. Load was all light bulbs, heating elements. wassbiplane
 

K D Redd

In Memory Of
Re: Frequently Asked MEP Questions

Are you speaking of a MEP-16? If so the engine needs to run at least 3600 RPM's for the generator head to generate 60 HZ power. At 2800 RPM, the powers frequency that the unit is generating is OUTSIDE the frequency meters measuring range.

Kent

P.S.
Harry, this topic needs mover from the FEQ section to it's own stand alone topic.
 

wassbiplane

Registered
Re: Frequently Asked MEP Questions

Thanks Kent, I was afraid to rev it up too much faster, as the voltage kept climbing.
I'll check out the 750 ohm volt adj pot & see if it's Ok & maybe try again.

Jerry
 

pegasuspinto

Registered
voltage was supposed to be 120 volts, it should stay steady as you get the RPM to 3600

why is there a load on the generator? at 3.9kw you had too much load

take off all the load and try again!
 

wassbiplane

Registered
3KW 120V AC genset-eng 4a32--V.R. # 6110-00-764-7621

OK, today I put the V.R. back In , fired it up, ran the governor up until the freq meter started working--(Hooray, it works)-set it on 60 cps---looked at Volts---160!!!So i thought I'd check the voltage on the exciter field--got varying & asstd voltages--seems like it wanted to give an A.C. reading---piddled around a little looked at Volts again-
Eureka--125 Volts---ran to get light bulbs--2-500watters---still 125V---only dropped about 1 cps---What did I do wrong ??-or Right---ambient temp was 90° F--but was sitting on hot sunny side of bldg--gonna try it again in the morning when it's cool & see if it still functions correctly....Jerry---ps . Anybody know what the little black sealed component on the pc board is--about 1.5 in sq. C 3/8" thick--looks like about 6 wires coming out & soldered into board.
 

wassbiplane

Registered
Well, tried again this morning in nice 70° weather---fired it up, let idle a while & let her go at 60cps---160 volts on the output---106 VAC on the field.
let it warm up a while--field voltage --no load 103 VAC---applied heater load
16 Amps--output dropped to 140V--field coil 93VAC--knocked around on various
components---No Joy
Does anyone have an old regulator I could buy for dissection purposes--you can't easily tell what's going on with the components wired in--too much interaction.---of course a schematic would be Ideal---then I could trouble shoot this SOB.
All replies appreciated--Jerry
 

Isaac-1

Registered
Last Subscription Date
01/12/2014
As a general rule generators should not be idled low like regular engines to warm up, doing so will burn out the voltage regulator as it will be trying to produce full voltage while the engine is running too slow. Doing so is probably the most common cause of voltage regulator failure on these MEP units since they have an easily adjustable throttle. You should start them then immediately (within 15 seconds or so) set the throttle to 60 hz. I know this goes against everything everyone has ever told you about caring for an engine.

Ike

p.s. I have a MEP-016B the diesel cousin of the unit you have
 

wassbiplane

Registered
Thanks Redd,flyinhorse & Issac!!
So what's a feller to do??--How do I fix the bad regulator??
I can only reverse-engineer this thing back so far-- what spooks me is that it worked for 30 minutes or so one time w/o me finding/ knowing the cause ,
The two major surplus dealers have sold out of regulators.
If someone has an old burnout,I could isolate & test some of the major components by cutting them out of the circuit.

Shore appreciate the help so far---Jerry
 

Isaac-1

Registered
Last Subscription Date
01/12/2014
You might try asking over at the steelsoldier web site, someone there may have a spare or know how to repair yours.

Ike
 

Jim McIntyre

Subscriber
Last Subscription Date
07/10/2019
160 volts on the output---106 VAC on the field.

Huh? 106 VAC on the field? Where exactly was this measured? The field typically runs in the range of 10-20 VDC.

Two things to be sure of before proceeding to diagnose a 'regulator' problem.

Thing 1 - make sure the set is running at 3600 rpm. (It will be providing 60Hz at only this speed, so a frequency measurement can conform this - but I'd not trust the 40 year old freq meter on the set.)

Thing 2 - check the voltage adjust potentiometer on the front panel. These get noisy, intermittent, and sometimes just had bad solder connections.
 

wassbiplane

Registered
What I was measuring was the voltage across terminals 20&21--also marked F1(+) and F2 (-)---which is actually the stator of the exciter.
I too thought the 100V~ AC was odd since the terminals ,wires etc are marked
Plus & Minus
I was using one of the "high quality" Chinese multimeters--$6.00 to 20.00,
depending on where you buy them.Digital display, the seem to be very accurate on voltages & ohms--but who knows , ???

The freq meter on the set seems to be fairly accurate, I haven't "beat" it against the powerline, but it checks with my old 15sec clock stopwatch rpm counting tachometer.

Thanks so much for staying with me on this problem. Jerry
 

wassbiplane

Registered
Kent, I was looking at your post on the Smokestack, and you closed with---Search the mobile power sub-form for the topic MEP-16? and pix----Is this on the Smokestack website??--I couldn't find it..

If you don't mind, could we talk a few minutes --@ your convenience--I'm retired--most any time.?

email your phone# & it's my nickel..

I just hate to tear into my regulator w/o exhausting all other possibilities.
 

K D Redd

In Memory Of
You have to watch some digital meters. Noise can get into the meter and cause bad readings. This engine SHOULD have the sealed/sheilded ignition system that is use on airchraft and by the military on spark ignition engines. If somwone has mangled the plug wire ends to use standard spark plugs, you may be getting ignition noise into you meter.
I will send you a Privat Message (PM) through this wed site with my Land Line Phone Number.

Kent
 
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