Another alternator Question

[Steel cowboy]

How can I test the 3 alternators I have off the bike. I’m trying to see if they charge or need rebuilding. I don’t want to take them apart, I’m looking for a way to bench test then maybe with a drill and my VOM.

[Dusty]

 Lots of auto parts stores have a test stand for alternators.  Electric motor with a pulley and belt to drive the alternator and connect leads to show the output.They test them for free in my neighbourhood.

 Dusty

[Ricky-D]

I agree that auto parts stores are set up to test alternators.

The main problem you run into with this is, however, that they have no way to

spin the alternator because of the drive that is presently mounted on the Honda alternator.

The drive is easily removed, but then having a pulley that can mount in place of the drive becomes problematic.

***

[Dusty]

I agree that auto parts stores are set up to test alternators.

The main problem you run into with this is, however, that they have no way to

spin the alternator because of the drive that is presently mounted on the Honda alternator.

The drive is easily removed, but then having a pulley that can mount in place of the drive becomes problematic.

***

Your right . I thought of that after I posted. I guess a trip to the hardware store to try and find a pulley that fits the shaft of the alternator is in order

Dusty

[MarkT]

I wonder how fast it needs to be spun.  IIRC the impeller screws on.  Don't recall if it's left or right thread. If the threads were protected with tape - or a coupler theaded inside were screwed on, a drill could spin it.  Would be a trick to unscrew the impeller.  It's not on there tight - at least one of mine wasn't.

[Steel cowboy]

My question also has to do with, were do you hook up and what is the polarity Used with 12 volts Needed to “excite” the winding to put out voltage. I am asking so if I needed To I could test it in the field. The plug on the side I believe is were you would inject the 12 volts, but which is positive and which is negative
I might be wrong and that’s why I’m asking

[gordonv]

I would think the wire is positive, and the body is the ground.

[Madmike]

My question also has to do with, were do you hook up and what is the polarity Used with 12 volts Needed to “excite” the winding to put out voltage. I am asking so if I needed To I could test it in the field. The plug on the side I believe is were you would inject the 12 volts, but which is positive and which is negative
I might be wrong and that’s why I’m asking

The schematic shows Black with green tracer as the power to the regulator and ground through the alternetor frame.

I double whether you can put out enough with a drill motor to load it up, I tried a 40 amp delco when I was a kida and it would stall a power saw when you hooked up the output of the alternator.  You may see Voltage but hard to say how many apms you will get.

You may have better luck getting a pulley at an auto parts place or  a scrap yard.  Most of the big Delcos are 5/8' shaft size, you may get something off a later model automotive alternator that would fit and would take a smaller shaft size, maybe even an import car one would work.   I suggest that you try for as small a diameter as you can find so that you can drive it faster.  The nuts are typically easily spun off the alternator using an air impact, some pulleys are keyed but to the shaft, lots are just held on by the nut.

[MarkT]

My question also has to do with, were do you hook up and what is the polarity Used with 12 volts Needed to “excite” the winding to put out voltage. I am asking so if I needed To I could test it in the field. The plug on the side I believe is were you would inject the 12 volts, but which is positive and which is negative
I might be wrong and that’s why I’m asking

The schematic shows Black with green tracer as the power to the regulator and ground through the alternetor frame.

I double whether you can put out enough with a drill motor to load it up, I tried a 40 amp delco when I was a kida and it would stall a power saw when you hooked up the output of the alternator.  You may see Voltage but hard to say how many apms you will get.

You may have better luck getting a pulley at an auto parts place or  a scrap yard.  Most of the big Delcos are 5/8' shaft size, you may get something off a later model automotive alternator that would fit and would take a smaller shaft size, maybe even an import car one would work.   I suggest that you try for as small a diameter as you can find so that you can drive it faster.  The nuts are typically easily spun off the alternator using an air impact, some pulleys are keyed but to the shaft, lots are just held on by the nut.

On the Valk alternator, the impeller IS the nut, it's threaded.  Don't know how you would drive that to remove it with an impact.

[Steel cowboy]

Ok let’s attack It from a different direction.  Would a VOM Allow me to test the alternator, With out taking it apart.

[Madmike]

There must be some different versions of this if the coupling is the nut, aftermarket service manual and parts fiche both show a nut backed by a washer securing the coupling.

you can partially disassemble (pull the back end off) and then test individual components with a multimeter.  Ken Hemings sold parts in the past.

[Warlock]

How can I test the 3 alternators I have off the bike. I’m trying to see if they charge or need rebuilding. I don’t want to take them apart, I’m looking for a way to bench test then maybe with a drill and my VOM.

May also try a impact. Spends faster and could watch your volt meter to see if it picks up higher voltage as you spend it faster. JAT
David

[indybobm]

find a socket that fits the nut and use a variable speed drill to spin it. Drill might have to be reversible.

[Madmike]

If you can get it turning and hook up the field wire, output and ground the frame you might be able to get 2 numbers, the first is output voltage, if this is good you could maybe do an AC test on the output and get an indication on whether the diodes are good or not.  Rotating the rotor by hand then at speed may let you know if the bearings are obviously ok.  If the drill stalls out then that could be an indication that the alternator is trying to charge the battery you are getting your field power from and is unable to drive the alternator, therefore it may be that the alternator is capable of producing good amperage.


Read this and there is a way to check diodes by switching voltmeter to AC range  https://electrical-engineering-portal.com/digital-multimeter-testing-car-charging-system

If you have access to a drill press with multiple drive sheaves you might get higher speed and more torque out of that than a hand drill.  Watch your thumbs.  Could maybe adapt something using two of the mount ears and a bar to hook behind the post to hold the alternator frame from spinning - mathematically the alternator output means you could have more than 1HP to hold on to.  Have fun.

Manual says peak voltage is 15.5 at 5000RPM engine speed so 2500 RPM cam speed, if that can't be attained then it is an indication of problems.

[The emperor has no clothes]

How can I test the 3 alternators I have off the bike. I’m trying to see if they charge or need rebuilding. I don’t want to take them apart, I’m looking for a way to bench test then maybe with a drill and my VOM.

Is the goal to have 3 backups ? Or, were you going to sell a couple ? I think the easiest way to test them is going to be to just install them on your bike and take measurements. You could probably replace the bearings and brushes pretty cheap.

[Steel cowboy]

Hey meathead (I hate calling you that but I don’t know your True name) lol. I recently picked up 3 Valkyrie alternators, they might even be for a gold wing. Anywho, I was trying to see if they were in working condition or just scrap he had sitting around. Installing them, just to test, is not an option to see if they work. Now that I’ll be towing the camper and the bike in the bed of the truck I wanted to set up a small Tote with a spare alternator, battery, small compressor and even some throttle cables, maybe more. I would hope I wouldn’t have buy an alternator as a spare just to sit around
Going camping in Blue Ridge Georgia in the fall.

[The emperor has no clothes]

Don't feel bad about calling me meathead.  It's who I am. (Rob) Having a spare alternator is a wise move. I have even resolved to carrying one in the bag on long trips. If you haven't changed an alternator yet, I would highly recommend doing one in the comfort of your garage. Having the experience of it is invaluable in a dark Motel6 parking lot. Camping in the Blue Ridge sounds great !

[Pluggy]

A volt-ohm meter can give you a dead or alive test.  It doesn't put any load on the alternator for a real performance test.  I have known guys to replace alternators only to find the problem is something else.  Often it is some component draining power to ground.