Power Equipment Forum banner
1 - 12 of 12 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter · #1 ·
Someone recently gave me an old Homelite WI-280 generator. It's not got a lot of hours on it and the Wisconsin engine sounds really solid and high-quality, so I really want to get this unit back into prime condition. It produces power now, but only 115 volts. I want about 122 so I found the regulator, intending to adjust it. But it's an open circuit board (not epoxy potted) and looks like what you would find in a small radio from the 1980's. I don't want to trust this regulator to keep the voltage right for my modern stuff. It also has no low-frequency voltage roll-off. So I am trying to find a voltage regulator that will work in my unit. Rotor winding needs 72 volts at 1.5 amps under full load. Regulator gets it's power from a "quad winding" that puts out 120 volts. The sensing input on the regulator could be either 120 or 240 volts. I would rather use a regulator with 120 volt sensing input, because this generator has a big switch that can select both windings in parallel for high amperage 120 volt or put the windings in series for 240 volts at half the amperage. I would not be able to use the high current 120 if the regulator required 240 for sensing input. One other requirement is that the regulator not depend on fan forced air for cooling. It is mounted in the "electrical box" with all the recepticles. There is not any room to mount it in the back of the generator, since the cooling fan is back there in this model.
 

·
Registered
Joined
·
1,519 Posts
Someone recently gave me an old Homelite WI-280 generator.
I don't want to trust this regulator to keep the voltage right for my modern stuff.
That's an old construction generator. What "modern stuff" are you planning to run?

Is it turning 3600RPM? Start with getting the frequency dialed in and see what happens with the voltage.
put the windings in series for 240 volts at half the amperage.
It doesn't do that. The two windings are 180 degrees out of phase and go to the two hot poles of the 240V plug. That's how you get 240V across them.
 
  • Like
Reactions: ToolLover

·
Registered
Joined
·
1,271 Posts
The OP I believe is correct to say that 240V is derived from two 120V windings in series, the "center tap" being the Neutral. But to your point, they also need to be wired out-of-phase so that the combined voltages are added up.

In 120V mode, the coils are electrically connected in parallel and in-phase. In such a manner, the coils are working together, adding up their current capabilities but the voltage stays at 120V.

Slope Rectangle Font Line Parallel


OP, I believe the engine is identical to the EY28. I have a generator of the same vintage with the latter engine... but mine's a Robin (Made by Fuji Heavy Industries in Japan). These are quality engines.

Anyway, detailed pictures would help. If it was a 90's-era machine, it's probably no longer in Homelite's website. They don't have anything older than 2010, it seems.
 

·
Registered
Joined
·
1,519 Posts
The OP I believe is correct to say that 240V is derived from two 120V windings in series, the "center tap" being the Neutral.
That's not really Parallel vs Series, which is this...


240V is strictly between the two hot legs; the line to neutral voltage is half the line-to-line voltage. Lighting and small appliances requiring less than 1800 watts may be connected between a line wire and the neutral. Higher wattage appliances, such as cooking equipment, space heating, water heaters, clothes dryers, air conditioners and electric vehicle charging equipment, are connected across the two line conductors. This means that (for the supply of the same amount of power) the current is halved. Hence, smaller conductors may be used than would be needed if the appliances were designed to be supplied by the lower voltage, and no neutral is required for balanced loads:
Table Rectangle Line Parallel Font



A switchable 120/240V generator is not a situation of parallel vs series, but a situation of in-phase vs inverted split phase.
 

·
Registered
Joined
·
1,271 Posts
That's not really Parallel vs Serial, which is this...


240V is strictly between the two hot legs; no neutral is even involved, for example in an electric oven, there are only the two hot leads and a ground:


The line to neutral voltage is half the line-to-line voltage. Lighting and small appliances requiring less than 1800 watts may be connected between a line wire and the neutral. Higher wattage appliances, such as cooking equipment, space heating, water heaters, clothes dryers, air conditioners and electric vehicle charging equipment, are connected across the two line conductors. This means that (for the supply of the same amount of power) the current is halved. Hence, smaller conductors may be used than would be needed if the appliances were designed to be supplied by the lower voltage, and no neutral is required for balanced loads.

A switchable 120/240V generator is not a situation of parallel vs serial, but a situation of in-phase vs inverted split phase.
Agreed, chalk it up as semantics. I know the distinction, just not the exact terminologies.
 

·
Registered
Joined
·
482 Posts
A switchable 120/240V generator is not a situation of parallel vs series, but a situation of in-phase vs inverted split phase.
I studied this on my small rotary a couple years ago - it has the voltage selector switch.

You are correct - it has to do with the phasing - that is the major key to it working. However, "parallel" is still at play. Just the "phasing" complicates it one more level.

Phasing gets in to AC circuits. Parallel is commonly referred to with DC circuits. However, the same Parallel term is at play with AC.

If you take a commercial prime install with 8 rotary gensets feeding the same building - how do you put all those 8 gensets on the same buss? Would you not say that those 8 gensets are running in "parallel"?

Therein lies the point on phasing - you have to get the AC power wave (should be 60hz in North America) to lay on top of itself - like an orchestra playing the same note on all the instruments - you get a nice resonance. If someone's cello is out of tune it sticks out like a sore thumb.

Same thing with your "paralleled" 120v coils on a gen. You don't have to worry about 8 engines spinning alternators at slightly different speeds until the frequencies line up as the poles of the alternator are spun by the same engine, but what you do have to do is reverse the polarity of one of the poles. That way the two halves are oriented correctly.

In order to do the above you have to split neutral. On 120v-only mode you take one of the hots and make it a neutral and one of the (split) neutrals (of the same coil) and turn that in to a hot - you put it in the circuit backasswards so the AC waves line up - in-phase.

There is a thread I did with some diagrams and 'scope traces on this a year or two ago... If you search my username I'm sure you can find it.

Edit - link to thread with diagrams etc:
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #8 ·
I agree about the phasing of the AC wave-form. I do understand that if you hook up two 120 windings in parallel but out of phase, you have a dead short. If you hook them up in series but in phase, you will run all your 120 volt stuff, but measured from hot to hot, you would have zero.
I have some pictures of the unit. I am new to this site, so I am not sure how to import pics, but I will have a go.
Motor vehicle Vehicle Automotive tire Bumper Plant
This is a unit identical to mine, except that on this one you can still read the writing on the control panel. I got this off the internet so I could see which way to switch the 120 only vs 120/240 switch.

Rectangle Schematic Font Parallel Engineering
This is the wiring diagram out of MY generator's electrical box.

Circuit component Passive circuit component Hardware programmer Audio equipment Electronic component
This is my voltage regulator. It lives in the electrical box. I know some of the capacitors have a lead de-soldered. I did that so I could check if they were bad or weak.

I do know this thing has to be older than Homelite can help me with. A few weeks ago, I called the people who bought out Homelite, and the guy was very nice, but told me that before his company bought out Homelite, Homelite themselves had something happen to all their archives of the older stuff. I can't remember if it was a fire or a computer virus, but it doesn't matter now. It's just simply gone.

Automotive lighting Automotive tire Fluid Bumper Automotive exterior
This is my generator's name plate. This is on the top of the actual generator, not the engine. It's located towards the rear of the generator. Perhaps you can recognize a date code on it somewhere. I have not yet looked for the engine's data plate. I assume it's stamped on it somewhere. If you can tell me where to look on this engine, that would be a help. From what I have read and the pictures I have seen online, it could be either a Wisconsin or a Robin or a Subaru.

Thanks to all who answered my post, and also for the lesson on speaking of the windings as being in phase or out-of -phase. I am sure I won't order an identical replacement regulator for this unit, because even the "new and improved" version is over $300, and I am not paying that. I will substitute a reg built for some other generator. I just need help finding the right one.
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #10 ·
Is the engine running at ~3700 RPM at no load? Have you tried adjusting the AVR to get 122V? What's the condition of the brushes and slip rings?
Yes, it's running about 3700 which is about 62 Hz at no load. Brushes still have over 3/4 inch of travel and the slip rings are making good contact. I fed the brushes with an adjustable DC power supply and was able to run 3600 watts (two 1600 watt hair dryers and a homemade 400 watt mini hot-plate) and maintain an output of 120 volts. I was feeding 72 volts and 1.5 amps to the rotor winding. I didn't try adjusting the AVR yet, because I don't like the looks of it and I want to replace it with something newer and (in my opinion) more trustworthy. That's why I am looking for a new regulator that can take in 120 volts from the "quad winding" and sense 120 volts from one of the output windings, and then put out the required 1.5 amps at 72 volts that is needed at almost full load. I know full load is 3800 watts, which would mean a bit more from the AVR. But if I could find a regulator that could give me 3600 watts, I would be happy. I don't plan to push it to it's limit anyway.
 

·
Registered
Joined
·
1,271 Posts
Here's my personal thoughts on the old regulator. I would rather use it IF it still proves to be functional and just needs some calibration.

I don't know much about using a universal AVR without taking things like winding resistance, etc. into account. I've previously asked a generator mechanic if an AVR such as the popular Stamford SX460 (or their clones) can be used on portable generators. The answer was, "it depends".

I would be wary about putting any AVR in there that is not specifically designed for it.

  • SX460 AVR - Automatic Voltage Regulator - Exact Generic Replacement
  • INPUT: Voltage: Jumper selectable 95-132V ac or 190-264V ac, Frequency: 50-60 Hz nominal, Phase: 1
  • OUTPUT: Voltage: Max 90V dc at 207V ac input, Current: Continuous 4 A dc, Intermittent 6 A for 10 secs, Resistance: 15 ohms minimum.
  • Regulation: +/-1.0% * Thermal drift: 0.05% per deg. C change in AVR ambient.
  • Unit power dissipation: 10 watts maximum - Build up voltage:4 Volts @ AVR terminals.
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #12 ·
I have looked at that AVR, too. I can't be sure from the description if it has BOTH sensing inputs (to connect to one of the main windings) and also an input for the "quad winding". I am also concerned because I see that the specs says it can put out 90 volts with an input of 207 volts. I can't feed it with more than 120 volts, since that's what the quad windings put out. So I don't know if it could put out my required 72 volts, since I will not be feeding it 207. My guess would be that it could, but I hate messing with returns.
I like the one listed on Amazon called a Devmo AVR AS440. It has separate sensing and power inputs. But again, it lists a good output at 200 volts input, but what happens when it only gets 120 volts?
I am also not sure about using a thyristor (triac, like a light dimmer) to control the field. Best as I can tell, these AVRs are for use in brushless generators that use a separate little generator section on the rotor to generate field current from a little stator to which the voltage regulator feeds current. I am a bit concerned because the pulses from a thyristor AVR might go into the field windings and be transferred to the main windings output. I would say this is less of a problem on a generator that has the brushless excitation system, since there are many more steps to go through to get to the main rotor winding. Those extra steps may dampen the pulses so that main winding output is not affected. Now, I have thought about putting a capacitor across the brushes of my generator to do the same thing. I do like the thyristor method of control, if pulses won't be a problem, because it runs cooler than linear outputs.
 
1 - 12 of 12 Posts
Top