i have seen some Thor grinders but not like this one, LOOK at the Amps its only 1/4hp over 7 amps i have never seen a 1/4hp grinder or any 1/4hp electric motor with that kind of Amperage, things probably a little power house. http://chicago.craigslist.org/nwc/tls/4973845316.html
Thor Bench Grinder.....C/L
- Thread starter tedsters
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drivesitfar
Well-known member
Tedsters: i actually own 2 of those cool little Aluminum Thor 1/4 HP grinders or maybe 3. i picked up one from a dentist and another one from a metal shop teacher that both loved them. i'm one day going to shine up one and put it on my small bench with this drill press and maybe my Wilton baby bullet vise.
it's a cool grinder, but that one looks a little worse for wear. maybe offer $10-20 and see if you can get it because i see one eye shield laying on top. BTW that old 1/4 HP grinder will probably out perform a lot of 1/2 HP imports that are measured differently now.
it's a cool grinder, but that one looks a little worse for wear. maybe offer $10-20 and see if you can get it because i see one eye shield laying on top. BTW that old 1/4 HP grinder will probably out perform a lot of 1/2 HP imports that are measured differently now.
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drivesitfar
Well-known member
Tedsters: I'm guessing Bob is right on, but i can't get to my Thor to tell you for sure even though i can see it on a shelf 40 feet from where i'm sitting. next weeks projects are piled up in front of the rack it's sitting on top of.
tool_scrounge
Well-known member
You are forgetting the power factor. P=V*I*PF
A lot of the small motors (lake shaded pole types) have pretty low power factors.
I've never heard of a power factor less than .7, and most are around .85-.95, so it is doubtful any ac motor could be that inefficient. And very rare for a shaded pole motor to draw that much juice. That 7.5 amps just seems wrong for a cheap grinder.
s/b 746 watts per horsepower.
oops, dyslexai rears its ugyl head. ...but the correct number makes my point even more strongly!
Yes, I know about power factors and Volt-Amps vs Watts, but the number given is so wildly out of line we need not be concerned with these fine points.
To put it in perspective, Thomas Edison had a generator (called the Long-Waisted Mary Ann) that was 97% efficient, and that was a century ago.
tool_scrounge
Well-known member
I have seen it once on a small fractional horse motor (old US made) that I scrounged up from the parents garage for a power hacksaw. I think it was a 1/6 HP motor and drew over 5A per my Fluke meter. Motor ran fine, but loading the motor did not change the current by much.
drivesitfar
Well-known member
I picked up a similar Thor 927 today, this one's a 1/3 hp. Same basic design with shaded pole motor and outrageous current rating of 8.5 amps! Cleaned up pretty good and after I dressed the wheels it runs well. Not in Baldor league, but an excellent grinder for DIY users. Massive self-aligning sleeve bearings built to last a long time. I'll make some Lexan eye guards for it and call it a day.
Note that the startup current was over 13 amps and running current was over 6 amps. Very likely it will indeed pull the rated current under load---I am stunned!
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wrenchguy
Well-known member
1958 Thor generator with original Clinton engine
