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modirt 
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Joined: 18 Jul 2018
Location: Missouri
Points: 8761
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 Posted: 16 hours 11 minutes ago at 7:51am |
That is a really good resource I wasn't aware of. This one might work........
That assumes 17mm is same as 0.625 diameter shaft on alternator. The math isn't exact, but close. Frustrating that they have to mix apples and oranges (SAE and metric) to to make it more confusing.
Past that........the plot thickens........meaning my education on all this continues. This from Powermaster (whose material is both excellent and abysmal).........
Edit: Measured and it's 6.25" / 2.65 = 2.358 (better than I feared, but still not good)
I'll have to measure, but my guess is OD of big pulley is no more than 5 inches.....turning a pulley of about 2 3/4"......so ratio is not much more than 2:1. At engine RPM of 1,000 fast idle speed, even this high amp alternator is not putting out much juice. Even in use in the field, engine rarely exceeds 2,000 RPM's. Documentation that came with alternator shows it tested to 65 amps at idle speed, but that was with 3:1 ratio. At my idle speed, may not be doing much at all.
So a lot of this then goes to operation. If working at night and are moving from field to barn.......and back........best let the engine rev......(do not shift up)......to get RPM's to 2,500 or more for as long as you can. Alternator really isn't doing much unless you do.
All part of the puzzle.
Edited by modirt - 15 hours 14 minutes ago at 8:48am
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modirt
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Joined: 18 Jul 2018
Location: Missouri
Points: 8761
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Posted: 15 hours 4 minutes ago at 8:58am |
Just got off phone with Powermaster tech support. Long story short, belts as now configured are good to go.
As per those guys, they don't have a 1/2" groove pulley for this alternator. Running high on those grooves at low speed not going to hurt anything. Pulley has OD of 2.65", so is faster than what I can replace it with, which BTW, the pulley is held on by some strange screw setup......maybe along the lines of a tamper proof setup. Not the nut and torque wrench change over some show to use. Best leave it alone.
Alternator kicks in at around 1,800 RPM alternator shaft speed, and comes up to rated speed at around 2,400 RPM, which at my fast idle speed ** will be around 2,400 RPM. Most transit and field work way above that, so should be OK.
** - Fast idle needed when unloading at the barn. Needed to turn the hydraulic pump to get drag chains moving, and is also needed to keep the radiator fan (runs on hydraulic motor) spinning fast to keep cooling system working. Those all speed up and slow down with engine speed. 1,000 RPM is about right.
Edited by modirt - 14 hours 55 minutes ago at 9:07am
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PaulB
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Joined: 12 Sep 2009
Location: Rocky Ridge Md
Points: 5116
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Posted: 13 hours 54 minutes ago at 10:08am |
Be aware that if the belts are not down in the groove where the top of the belt is flush with the pully, you are effectively running a larger diameter pulley. Measure what you get for the OD of the belts around you alternator pulley. Do you have a mechanical tachometer that you can actually measure the alternator RPM ?
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If it was fun to pull in LOW gear, I could have a John Deere.
Real pullers don't have speed limits.
If you can't make it GO... make it SHINY
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modirt
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Joined: 18 Jul 2018
Location: Missouri
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Posted: 13 hours 33 minutes ago at 10:29am |
Good call.....it may be sitting 1/8" or so proud, so maybe 2 3/4" plus effective diameter of pulley. The one from Brillman better than that, and 1/2" to boot. If I can figure out what "special tools" are needed to make the swap.
No.....do not have a shaft RPM. Just tach on the engine.
But do have an electric meter, so may be able to measure voltages and amps when running to see what I got.
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steve(ill)
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Joined: 11 Sep 2009
Location: illinois
Points: 87992
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Posted: 10 hours 53 minutes ago at 1:09pm |
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alternator output is not linear.. Generator output is relative to SPEED... Alternator might take some RPM to kick in, but after that the output is a curve.. running half speed might get you 75% output..( 1200 engine rpm, 2500 rpm alternator).. they are all a little different, but the main advantage of an alternator is good amp output at lower rpm as compared to a generator. .... once an alternator goes above 3000 rpm the output starts to go flat...
Edited by steve(ill) - 10 hours 46 minutes ago at 1:16pm
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Like them all, but love the "B"s.
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iowallis
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Joined: 04 Jun 2017
Location: North Iowa
Points: 372
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Posted: 8 hours 45 minutes ago at 3:17pm |
 modirt wrote:
Frustrating that they have to mix apples and oranges (SAE and metric) to to make it more confusing.
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And make things simple?? I have done repair work on late 1970s to late 1980s vehicles that are mish-mash of metric and SAE bolts/nuts. There was one manufacture (Chevy?) that 2 out of the 3 starter bolts were metric and the other SAE. Then the Ford 5.4 oil filter, supposedly the engines built in Windsor Canada has SAE threads on the filter and the engine built in Romeo MI (USA) has metric threads.
Sound like you are making much progress on this project, might as well go all the way and restore it to its original, as sold when new, glory.
Edited by iowallis - 8 hours 44 minutes ago at 3:18pm
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Les Kerf
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Joined: 08 May 2020
Location: Idaho
Points: 1312
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Posted: 2 hours 53 minutes ago at 9:09pm |
modirt wrote:
Just got off phone with Powermaster tech support. Long story short, belts as now configured are good to go.
As per those guys, they don't have a 1/2" groove pulley for this alternator. Running high on those grooves at low speed not going to hurt anything. Pulley has OD of 2.65", so is faster than what I can replace it with, which BTW, the pulley is held on by some strange screw setup......maybe along the lines of a tamper proof setup. Not the nut and torque wrench change over some show to use. Best leave it alone.
Alternator kicks in at around 1,800 RPM alternator shaft speed, and comes up to rated speed at around 2,400 RPM, which at my fast idle speed ** will be around 2,400 RPM. Most transit and field work way above that, so should be OK.
** - Fast idle needed when unloading at the barn. Needed to turn the hydraulic pump to get drag chains moving, and is also needed to keep the radiator fan (runs on hydraulic motor) spinning fast to keep cooling system working. Those all speed up and slow down with engine speed. 1,000 RPM is about right.
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It will be just fine. Install a voltmeter if you are concerned (a voltmeter tells you far more than does an ammeter).
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