anybody running a pm head?

[rcavictim]

Welcome to the forums Bill!

The observation you made is valuable to know.  Taking precautions such as you suggest by using a magnetic structure at the cooling air inlet of a PM alternator sounds like a good idea.

As far as stuff jumping around on your computer screen, have you tried holding it in place with a piece of scotch tape?  As you can see I'm clearly the person you want to talk to for practical solutions to common computer problems! 

Sounds like you have a keen interest in woodshop stuff.

[mike90045]

I use a magnet to hold stuff on the computer screen.  Pretty rainbows and such...

[rcavictim]

I use a magnet to hold stuff on the computer screen.  Pretty rainbows and such...

Great idea Mike.  That will also keep airborne ferrous metal particles from clogging up the pixels!

[Bill]

I use a magnet to hold stuff on the computer screen.  Pretty rainbows and such...

Hello Mike,

This time the screen is stable and no problems with jumping below the border..

When we had "Computer Lab" for my PreK to 6th grade elementary campus, the lab teacher came into my office with a student and mad as a wet hen.... ;>)  She took pride in her job and equipment, and expected that of her students, too.

Ten years ago, the monitors were CRT screens, and a student had taken a magnet and moved it across the screen...  Made quite a mess. The student and she thought it was damaged beyond repair...  After dealing with the student's isolation at lunch and playground time, and putting him back in his home room class, I told her to degauss the monitor by repeated On and OFF cycles.  I learned later, it took longer than I thought, but she fixed it....

Speaking of things that "stick on things"... The computer teacher had one standing MAJOR rule, and your posting reminded me to laugh...because I didn't realize that certain things stuck to plastic because they were "Magnetic"....   Her verbal reminder to each class, could be heard each week.  It was:
 "Other students use the same computer you do.  While you are practicing your keyboarding skills here in the lab, DON'T PICK YOUR NOSE."

Bill

[rbodell]

I saw this thread and remembered that a few years ago I bought a PMDC motor from Surpluscenter.com to build a welder out of. It's like 36 volts and 160 or 180 amps or something like that. As it turned out, I couldn't find anything that would match the spline on the shaft as it was evidently special made for the military or an aircraft. I even went to a machine shop to have a coupling made for it but none around here can do inside splines. Now I am getting an urge to try to do something with it. Since the shaft is tempered, I think I can make a keyway in a double belt pulley to match one or two of the splines. I feel a project coming on.

[bschwartz]

I believe he means that the coupling would need splines cut on it's inside to match the splines on the outside of the shaft.

[rcavictim]

I believe he means that the coupling would need splines cut on it's inside to match the splines on the outside of the shaft.

That would be a cake walk but the solution is somewhat permanent.  Machine a bushing that has a smooth borehole that is a friction fit to the OD of the externally splined generator shaft.  The other side of the bushing should have whatever "normal" connection you wish to use, eg, splined smooth shaft with keyway.  Press it on and weld it to the gen shaft.  You could add a hole or two along thew length to expose the spines neneath and plug weld it also.

If you are dealing with a female splined input on your generator that is a much more serious challenge.  I recently had to deal with such a situation myself.  I had a nice compound would 36 volt, 12 HP, 2100 RPM DC motor which I needed to use as the starter motor for my wnid turbine proiject.  It was a hydraulic pack out of a forklift originally. After getting no-joy from visiting local machine shops and not wanting to destroy an expensive Sesna made hydraulic pump for the splined shaft section I took on the project myself.  What I did was to start with a piece of 1" OD cold rolled mild steel.  First I turned a couple of inches off the end down to the OD necessary as the spline OD.  This allowed perfect centering later. With the help of a vice and hand held angle grinder with 1/16" thick cutoff wheel I was able to machine the splines using a vice jaw as a straight guide for the cutoff disc.  Tapping the shaft into the hardened female splined hole in the motor shaft with soft hammer blows as I went made marks that I was able to use to guide my grinding.  Eventually I got the spines a perfect fit!  The last part to slip in was turned to be a tight press fit with the help of my lathe. The final product is absolutely true within less than 5 thou radial runout and well within working tolerance for a V-belt pulley.  Using the vice jaws as a guide I also made a keyway in the shaft.  The whole job only took a couple of hours.  Once done I ran a bead of 308 SS 1/16" stick weld around the exposed union right at the motor end plate.  This job is veversible with a grinder but otherwise permanent and I am now the proud owner of a big DC motor that is actually 'useable'.  

It would be nice to own a mill but I don't see this expensive machine tool in my future.  I absolutely could not survive without my lathe however.

[rcavictim]

One more picture showing my handmade splined shaft.

[rbodell]

I believe he means that the coupling would need splines cut on it's inside to match the splines on the outside of the shaft.

That is correct, on the outside of the shaft

[rbodell]

I believe he means that the coupling would need splines cut on it's inside to match the splines on the outside of the shaft.

That would be a cake walk but the solution is somewhat permanent.  Machine a bushing that has a smooth borehole that is a friction fit to the OD of the externally splined generator shaft.  The other side of the bushing should have whatever "normal" connection you wish to use, eg, splined smooth shaft with keyway.  Press it on and weld it to the gen shaft.  You could add a hole or two along thew length to expose the spines neneath and plug weld it also.

If I got this correct, are you talking about a browning type of bushing? I thought of that but I was concerned about the reduced surface area due to the splines. I haven't given up on welding either, but I want that as a last resort.

[rcavictim]

I believe he means that the coupling would need splines cut on it's inside to match the splines on the outside of the shaft.

That would be a cake walk but the solution is somewhat permanent.  Machine a bushing that has a smooth borehole that is a friction fit to the OD of the externally splined generator shaft.  The other side of the bushing should have whatever "normal" connection you wish to use, eg, splined smooth shaft with keyway.  Press it on and weld it to the gen shaft.  You could add a hole or two along thew length to expose the spines neneath and plug weld it also.

If I got this correct, are you talking about a browning type of bushing? I thought of that but I was concerned about the reduced surface area due to the splines. I haven't given up on welding either, but I want that as a last resort.

All that the thin outer surface area of the splines is needed to do is maintain centering of the outer added bushing.  Your welding it to the splined shaft is what will carry the power torque.  The only reason I would hesitate weding onto the splined shaft is if it creates difficulty replacing the bearing on that end of the generator.  If that is not a problem then weld away.  It isn't like you plan to use that stupid spline system.  If you could use it, you'd be doing so now.  If you weld, use 308 or 309 stainless rod.

I am not against splines per se.  They are likely the best shaft coupling possible, but I refer to them as stupid when nowhere in industrial supplier inventories on the planet are mates available to fit them.  They are certainly not DIY friendly.

[rcavictim]

By the way, I'm having trouble typing in this box as the last few lines keep jumping down under the bottom border even though I have extra blank spaces below this.  Any ideas how to correct this distraction?

It''s good to be here,
Bill


I am having the same problem recently and figure it is the fault of a recent ill conceived version of Microsoft Updates.  The most likely cure?  Stop using garbage Microsoft  software.
 

[Henry W]

By the way, I'm having trouble typing in this box as the last few lines keep jumping down under the bottom border even though I have extra blank spaces below this.  Any ideas how to correct this distraction?

It''s good to be here,
Bill


I am having the same problem recently and figure it is the fault of a recent ill conceived version of Microsoft Updates.  The most likely cure?  Stop using garbage Microsoft  software.
 

I had the same problem untill I dumped internet explorer 8 and went back to internet explorer 7. Now I have no problems at all.

Henry

[rbodell]

All that the thin outer surface area of the splines is needed to do is maintain centering of the outer added bushing.  Your welding it to the splined shaft is what will carry the power torque.  The only reason I would hesitate weding onto the splined shaft is if it creates difficulty replacing the bearing on that end of the generator.  If that is not a problem then weld away.  It isn't like you plan to use that stupid spline system.  If you could use it, you'd be doing so now.  If you weld, use 308 or 309 stainless rod.
Thanks for that. maybe that is what I should do.

I was just thinking, what if I fill the splines with JB Weld. Do you think that would give enough friction to use a browning bushing?


I am not against splines per se.  They are likely the best shaft coupling possible, but I refer to them as stupid when nowhere in industrial supplier inventories on the planet are mates available to fit them.  They are certainly not DIY friendly.
[/quote]

[mike90045]

First numbers are in

frequency  leg 1 load   leg 1 voltage   leg 2 load   leg 2 voltage  total load
    61           0 W            121.2 V           0 W         121.3 V           0 W
    60.3       890 W          118.1 V           0 W         120.2 V         890 W
    59.9      1525 W          116.3 V           0 W         118.9 V       1525 W
    58.8      1415 W          113.7 V        1650 W       114.9 V       3065 W
    58.6      1765 W          116.8 V        1610 W       113.3 V       3375 W

Metro 6/1 on WVO (soybean)  4200 ft elevation, Georgia Generator 6.5k PMG
all readings from two kill-a-watts  (the last readings had the Kill a watt on leg 1 flashing)

I don't think the engine will do much more without heavy smoking, but not bad for free fuel.

Amazing.  I don't understand what keeps the regulation so good with variable loading, is it just overkill in the windings, or is there an AVR somewhere ?