Snow Mobile Regulator

[Reloadron]

A co-worker came up to me with a question or two. I don't own a snow mobile, never did and likely never will. He ownsa a 1994 Polaris XLT SP snow mobile. His version is pull start (no battery or starter motor). Apparently these creatures have some sort of alternator with a regulator and produce 12 volts (I guess DC) for accessories. I don't know? I am asking. A problem seems to be these things use a regulator (I have heard it called a two wire regulator). I am not even sure if the alternator is similar to 3 phase automotive or single phase whatever alternator. The problem is the regulators burn out. There are aftermarket versions from Taiwan labeled to be 200 Watt units and they have a short life. Typical cost $20 USD. Not much but they don't last. Trying to find reasonably priced OEM is difficult and once found they cost much more and still tend to burn out after use.

These regulatiors, on fail generally just allow open voltage which can quickly burn out the headlamp which on a cold dark night can be a real problem.

Question is, anyone here familiar with these systems? How difficult would it be to come up with a reasonable replacement? Meaning a design that won't burn out on a regular basis. I just have no knowledge of the snow mobile electrical system. I don't even know how they make power beyond possibly some form of alternator. So if anyone here has one of these animals or similar and could provide some insight it would be most appreciated.

Ron

 

[MikeMl]

It is a shunt regulator. Moulded into a brick, so you cannot get into it. If you run with head light on during daylight hours, the regulator dissipates less than it would with the lights off.

 

[Reloadron]

It is a shunt regulator. Moulded into a brick, so you cannot get into it. If you run with head light on during daylight hours, the regulator dissipates less than it would with the lights off.

Thanks Mike. From how it was described that would fit. Moulded brick is how it was described. So they use a shunt regulator, thanks a lot.

Ron

 

[kinarfi]

My experience with this type of power comes mostly from motor cycles, I did own a snow machine or three a long while back and I'm thinking they are 3 phased wye connected, but if I was to try to solve the problem today, I would start with a full or half wave bridge into a large capacitor and then a dc to dc regulator or converter. Check and see how many wires are coming out of the generator/alternator.
Kinarfi

 

[crutschow]

Where is the regulated mounted? Adding a large heat-sink should improve the reliability.

 

[Jaguarjoe]

Olser Suzuki GS motorcycles had notoriously unreliable regulators. The common practice was to replace them with bulletproof Honda units. Typically $35 used on fleabay. For more specifics search the GS Resources web site Electrical/Ignition - The GSResource Forums for a guy named Duanage, he sells regulator kits.

 

[Reloadron]

Saw my coworker today real brief. He did have a schematic but before I could really look at it things came up. From what I saw in a quick glance it is a two wire regulator, just as was suggested. Not even a bridge in there. A single line looks to come off a stator on the engine and the regulator is a shunt to ground. All the thing has is built in hand warmers (2 stage), a few lights and a two beam headlight. He did tell me he ordered a $60 OEM regulator from Polaris.

I will ask tomorrow (he comes in for second shift) about the mounting. Maybe we can improve on that. Thanks.

Thanks to all who have come up with info on this.

Ron

 

[KeepItSimpleStupid]

I may have to look at some info I have on systems that are used for snowthrowers. I do know they do some wierd things to operate the lamps. These are basically 120 VAC start, but it has the ability to operate a lamp. From what I remember, they may use +12 for one ;amp and -12 for the other, so there is a diode pack.

 

[KeepItSimpleStupid]

I took a look at my B&S L head repair manual and there are many different alterntor systems. Some are just used to trickle charge a battery say at 1.5Amps or so.

Some of the more specific systems (not all of them) include:
1. AC only alternator for lights

2. Dual dircuit alternator
2a. DC is unregulated
2b. AC to lights

3. Tri-Circuit alternator
3a. DC to lights
3b. DC unregulated for charging (resitor limited) and clutch

4. Quad circuit alternator
4a. DC to lights
4b. Regulated to battery (current regulator)


5. Regulated alternaor (DC is used to charge battery)

The strength of the magnets determine the output. Some of the systems supply a negative voltage with respect to ground for the lights.

A shunt regulator or a clamp type system probably makes sense for the snowmobile.

Now let's add some stuff from experience.

Filaments last longer when DC is used.

Vibration can cause the filaments to short or short briefly. I can remeber when I was about 16 YO, I was driving and suddenly the headlights on my car started to blink at a low rate. The breaker was built into the light switch and was thermal. One of the headlights actually shorted.

The quality of the headlamp will play a role.

Thus thermally or fused headlamps should be used. Varistors and transorbs should be employed. If slow turn-on could be provided for the lamps, that would even be better.

A low-drop out series regulator (switching) might not be a bad choice with current limiting, but one needs to determine if the lights are AC or DC. That will be an expensive upgrade. We might be talking 100 Watts or so.

PWM might work as well. There is a nice PWM kit from Jameco that might show some promise. Again you need to figure out if the lights are getting AC or DC.

My guess is unregulated AC that's possibly clamped.