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Need Voltage Regulator

PFT

Sponsor
Last Subscription Date
02/07/2020
I need to get a regulator for this genset. I use a reostat to adjust output volts now as the original regulator was missing when I got the set. It runs great and makes power, but does not self adjust to load changes. THANKS
 

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PFT

Sponsor
Last Subscription Date
02/07/2020
Sorry for the brief message, but my computor keeps going off line and thinks it is still on. I will try a couple more pics and give you more info. The reostat I'm using is rjs500, 500 ohms,0.316a. It is capable of adjusting thru the range I need. I will try to supply more info as needed. THANKS again, Paul
 

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Jim Rankin

Registered
Age
58
What is the voltage at the point where you have the resister? I see the DC exciter is 125VDC, can't see the amp rating in the picture. I have a couple of Basler KR7FF regulators and they are available on ebay pretty regular. I believe that regulator would replace the DC exciter and it's regulator and supply the 125VDC field up to 3.5 amps output.
 

mylesdw

Registered
So am I right in thinking that on that style of Century alternator with the built-in DC exciter that voltage to the AC field windings is actually regulated by adjusting the voltage to the DC field windings and the DC generator output drives the AC field directly? If I understand correctly, a solid state regulator can replace the DC exciter and its 'mechanical' regulator completely and would drive the AC field directly. Where does the regulator get its power from? Is this the residual magnetism and 'flashing the field' thing?
 

PFT

Sponsor
Last Subscription Date
02/07/2020
Jim, the tag on the exciter says 4. amps. I fired the unit up tonight and took readings at both sides of the resistors ( 2 fixed and the reostat ). From the F1 terminal to neuteral was -5 volts, A2 to neuteral was 54 volts, and F1 to A2 was 60 volts. The resistors are all in series between F1 and A2. The only load I had on it was a 15 hp 3 phase motor running free. In case anyone is interested, the engine is a Waukesha 130HL spark ignited diesel built in march of 1943. Hope these numbers help you understand this thing. THANKS again and special THANKS to Harry for this board. Paul
 

Jim Rankin

Registered
Age
58
mylesdw said:
So am I right in thinking that on that style of Century alternator with the built-in DC exciter that voltage to the AC field windings is actually regulated by adjusting the voltage to the DC field windings and the DC generator output drives the AC field directly? If I understand correctly, a solid state regulator can replace the DC exciter and its 'mechanical' regulator completely and would drive the AC field directly. Where does the regulator get its power from? Is this the residual magnetism and 'flashing the field' thing?
I'm no expert, but I believe you are correct on all counts, though there may have been different ways of doing it. The old style mechanical regulator initially gets it's power from the residual voltage created by the residual magnetic field in the DC exciter.

Some sets have a flashing relay or switch terminal that energizes the field while the starter is actually cranking the engine over. By the time the starting switch is released, the engine speed is coming up and the exciter is making voltage which feeds back through the regulator. It would take a wiring schematic to make sure how all this is done in a specific set.

Most modern sets did away with the rotating DC exciter generator with it's brushes and commutator and rectify the AC output of the stator or the AC output of a dedicated winding in the stator to power the regulator and field. This is a so called static exciter vs the rotating exciters.

When heavy surge demand is anticipated, modern sets are equipped with a permanent magnet alternator to power the field. This independent source of power for the field is less affected by starting surges of large motors or other large block loads that cause stator output voltage to sag. So it looks like to me we have gone full circle and are back to the rotating exciter, without the brushes and commutator, but with rectifiers instead. Much more reliable and cheap now-a-days.

Then you get into brush and brushless exciters, and that is where the rub is when converting to modern regulators. The not so old statically excited brush type sets I have seen tend to have high amperage-low voltage exciters compared to the brushless which can multiply the output of a small regulator through the brushless exciter stator and exciter rotor to create the power necessary for the main field.

Finding a modern, off the shelf, regulator capable of powering some fields directly is hard to do. So you wind up with a complete regulator and exciter system like the Powertronics system that has been mentioned on the board. Still can be cheaper than repairs to some older regulator systems and you have modern equipment with tech support etc available.

Just my experience, and I'm learning too. My generators include a `44 Buda with a Century generator end, Late `60's early `70's Onans and a Caterpillar
 

Raymond

Registered
Age
71
The Basler KT-3B is a transistor replacement for the old mechanical regulators. It is rated 125 v.cont 200 max armature, 2 amps forcing 6 amps and a minimum 34 ohm field res. This may work but Basler likes their stuff a lot. I believe the last time I priced one it was around $400.
 

BenHuebner

Registered
Wouldn't it somehow be possible to make use of the Rotating DC exciter generator by using a modern regulator on the field coils of the excitor. The big question would be how to hook it in with the brushes, field coils, shunt coils etc.
 

Raymond

Registered
Age
71
Thats what the KT-3B does. It senses the voltage in one phase of the stator output and has taps for 120/208/240/416/and 480v. 3 volts residual will produce sufficient armature voltage which powers the regulator to control the exciter field. It is a direct replacement for the old electromechanical units used on the older brush type dc exciters.
 

PFT

Sponsor
Last Subscription Date
02/07/2020
OUCH:eek: , that's half what I payed for the unit. I was hoping to find a less expensive way. Anybody know how to build something for less, I know some people capable of helping me assemble electronic stuff. Thanks Paul T.
 

Jim Rankin

Registered
Age
58
I don't know why they come up on ebay often, they must fit something common, but if the KR7FF regulator will handle the load, you can get one eventually for less than $400 or I'll sell you one of mine.

About 6 months ago, I forgot to bid on an auction of 3 of the KT3 type.:mad:

I have a Winco 45kW 3 phase set that has a KR4 I believe it is (63 Volts instead of 125 for the KR7). That's it, not much to it. Connections to single phase AC (2 lines) for power and sensing, F1 and F2 output to the brushless exciter stator and connections for a panel control to adjust the voltage if desired.

I'm sure there's a bundle of stuff in the box, but it does make a compact installation.
 

enginenut2

Registered
Age
78
A real live Waukesha-Hesselman

Paul F. Thompson said:
Jim, the tag on the exciter says 4. amps. I fired the unit up tonight and took readings at both sides of the resistors ( 2 fixed and the reostat ). From the F1 terminal to neuteral was -5 volts, A2 to neuteral was 54 volts, and F1 to A2 was 60 volts. The resistors are all in series between F1 and A2. The only load I had on it was a 15 hp 3 phase motor running free. In case anyone is interested, the engine is a Waukesha 130HL spark ignited diesel built in march of 1943. Hope these numbers help you understand this thing. THANKS again and special THANKS to Harry for this board. Paul
Paul, That engine is not a diesel but a Hesselman oil engine built under license by Waukesha.
The early small diesel engine was not easy to love and Waukesha had in the early 30's built some L head diesels but stopped to make a line of the Hesselmans which had a lot going for it compared to the diesel of the day.The Hesselman burned diesel fuel or similar fuel oil at moderate pressures and a compression ratio of 5.5-6.5 so it was lighter,quieter, ran at higher speed, could be started as easily as a comparible gasoline engine, and gave very similar power/efficiency to a full diesel.It was spark ignition and the fuel was injected directly into the combustion chamber.Usually a small amount of gasoline was squirted into the manifold for starting then discontinued as the engine picked up on oil.
My manual of 1945 indicates your engine is a modified version called a "multi-fuel oil engine" as indicated by the injectors being on the exhaust side of the head or opposite of an industrial version.They say the engine can run fuel injected on oil or gasoline with only a change of injection and spark timing, or remove the injection pump, plug the injector holes, and add a carb for the use of gasoline in that manner.The pump drive coupling will be marked for the appropriate position for the fuel used.
The 130 HL is 4" X 5" and rated continous 55 HP @2200 RPM.The big industrial waukesha Hesselman was 8.5" X 8.5" and 333 HP @ 1050 RPM.These were used as big truck engines and Allis-Chalmers built and pushed them instead of diesel until they bought Buda in the mid 50's.

Hope you have fun with this scarce and unusual engine.
 

PFT

Sponsor
Last Subscription Date
02/07/2020
Enginenut2, you are absolutely right on all counts. I was wondering how long it would take for someone to notice the oddity of this engine. I have the "General Instructions for the care and operation of Waukesha-Hesselman Oil Engines" manual, and also the parts book for the 130HL. The manual covers the complete series of W-H engines. Although the engine is not a true diesel, it is called a diesel on the tag, should have taken a photo when I had the injector pump off to fix the bushings in it's drive. The unit was assembled by the Rodgers Diesel and Aircraft Corp., anybody know anything about them. Does anybody know of any more of these engines around, mine is the only one I have seen. Thanks Paul T
 

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Jim Rankin

Registered
Age
58
Very interesting engine. I see some "multifuel" military engines that apparentely were used in trucks etc. Have never seen any up close and always wondered how they worked and how "multifuel" capable they really were.

How did you come up with the Waukesha-Hessleman set? I don't know where the BUDA I have was until we bought it in the early 1990's. How does yours run, does it like cold etc? Do you use gasoline to start. I know some of the old JD 2 cylinders used gasoline for starting somehow, and then switched to tractor fuel. I think their early 2 cylinder diesels were gasoline pony motor start for the most part.

Diesels were a problem to start in the old days that's for sure. I believe BUDA and GM had the starting figured out better than Caterpillar since they mostly used direct electric start while CAT stayed with the pony motor as standard equipment through the 50's. On the other hand I have heard of a man with a snow shovel and a can of gas going out into arctic winter and retrieving a D9 that had been sitting for months. That wouldn't happen very often with electric start.

Hope you can get it to regulate. Let me know if you think the Basler regulator is worth a try.
 

PFT

Sponsor
Last Subscription Date
02/07/2020
Don't know it's orginal use, but apears to have navy gray on top of army green paint. A friend found it in a barn when he went to buy a backhoe and bought it also. He stored it in his barn for a few years until I decided I needed backup power the summer after our big labour day storm of 98. Took awhile to get it set up ( had to build a shed ) and fgured out. Runs super and is not loud outside with the Farmall M muffler, loudest thing inside is the fan. Starts in 2 or 3 turns in winter with a shot of gas from the primer pump and nozzel in the intake. In cold weather it may take a few more shots of gas to keep it going until it gets a little heat in it. Govenor operates a butterfly in the intake and manifold vacuum controls the injector pump :crazy:. Only time it didn't start was in Jan 05, very cold, when a tractor trailer took out a power pole, the 6 volt battery didn't have enough oomph to crank it. I now have a 12 volt battery connected to it thru 2 push button starter switches to isolate the battery from the genset. Spins it like crazy. I would look on ebay for a regulator if I knew what models would work for sure. Don't want to buy one and then fry something if it's not right. Thanks for the replies. PT
 

armandh

Sponsor
Last Subscription Date
09/02/2010
regulation is a form of inverse feedback. since the DC generator drives the alternator field changing the dc gen field will vary the ac output volts.
Ive been thinking about a regulated dc supply at a higher voltage than the normal field voltage bucked down by opposing unregulated dc isolated and rectified from the AC output. now the tricky part, it is not volt for volt. varying the dc gen field leaves one working with lighter currents but there is a factor of amplification.
you need to determine what changes in [dc gen] field voltage produce what changes in the output. a transformer for the unregulated supply with lots of taps driven by a variable autotransformer should make a nice test rig to get the right ratio.
 

armandh

Sponsor
Last Subscription Date
09/02/2010
PS maybe an inverter supply from the batteries to feed the regulated supply
another way would be to run the dc gen at a higher voltage and a heavy pass transistor to feed the ac gen field, the [usually emitter follower ] controlled by an unregulated supply from the ac gen output.
 

Raymond

Registered
Age
71
Where is the voltage sensed and how does it compensate for load changes. What controls the output of the dc exciter? With the exciter field shorted for full output it will burn itself up. If set at a fixed voltage with a rheostat the power output level of the exciter will be fixed. You have to control the current (and hence the power output of the exciter) in the exciter field as a function of the stator voltage which varies with load. Otherwise you must remove the dc exciter and use a static exciter like the Power-tronics SE 350. There are 2 regulators that will work; Basler kT3, and SR8. The KT is around $400. and the SR8 around $1800. The power-tronics with the SE350 (may take a 450) with a UVr500 regulator is around $400. The static exciter system will out perform the Dc exciter by more than a factor of 2 in every aspect. If the control of generator voltage was simple, Radio shack would sell kits and Basler and power-tronics wouldn't exist. Its just a guess but over half of the generator problems are with the regulator, the rest are fuel and governor problems.
 
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