

Why would you say that? Many motors are listed for 50-60 cycle use. You get a different speed, but...
I don't post much in here, but thought I would share this. Had to go to the other side of town today for a training seminar, two sales down the street and $15 later, I can finally join the craftsman RHFT ratchet club. Not pictured is a stack of ~500, official 100 yard small bore rifle targets, to windy to get them in the pic. 
I was told by an electrician not to plug in an antique fan that was labeled 115v 50hz because it would damage the motor. Something about excess heat.
On anything that old you need to inspect all the wiring before plugging it in anyways. There is almost always cracked/missing insulation.
Motors: Changing between a 50 and 60Hz supply.
faq237-1224
Posted: 20 Mar 06 (Edited 9 Jul 06)
Due to the frequent questions about running motors at "the other frequency" this FAQ was created.
This FAQ is directed at other engineers and so will contain details the average user may not care about. You are invited to pay attention only to what is useful to you.
This FAQ applies to induction motors, both single, and polyphase. Single phase motors have an added aspect that will be discussed at the end of this FAQ.
AC motors are quite complex for all their functional simplicity - turn them on they spin.
There are a huge number of interacting relationships in a motor's design. There are first order, second order and probably even third order aspects that are all balanced to produce a dependable motor with the desired characteristics.
This FAQ will deal only with the First Order aspects.
These complexities include:
1) Rotational speed is a direct function of the power frequency.
2) Cooling is a direct function of rotational speed.
3) The magnetic capacity of the motor's magnetic(iron) circuit is designed to the relationship: voltage/frequency (V/f).
4) Back-emf decreases as a motor slows down.
5) Current increases with reduced back-emf.
Lets look at these complexities each in turn.
If you drop the frequency the motor will slow down.
If you raise the frequency the motor will speed up.
If the motor slows down it's cooling will drop (and at a faster rate then the slow down).
If the motor speeds up its cooling will increase rapidly.
If the frequency drops the V/Hz goes up. This means that the motor needs a larger magnetic circuit. Without it the magnetic circuit can saturate. This leads to a rapid increase in current draw and a corresponding large increase in temperature.(A motor's chief enemy)
If the frequency increases the V/Hz drops. This is not a first order consideration. [The motor may have a worse power factor.]
A motor is a device that 'wants' to turn at its designed speed, set by its designed operating frequency. It delivers the required horsepower(hp) the load needs when the load is spun at the motor's designed speed. Different loads change their hp demands in very different manners, depending on the type of load they are.
If a motor's load increases for some reason the motor will be slowed, this means the back-emf drops, this causes the motor to draw more current. More current is where the motor gets more power to turn the heavier load. Here the prudent motor user makes sure that the motor is pulling less current then the motor's full load amperage(FLA) rating.
If the load remains the same and the voltage is lowered the motor will draw more current to continue meeting the load's hp requirement. Remember the motor will still be running at the same speed since the frequency wasn't changed.
So looking at the case shifting a 50Hz motor to 60Hz duty.
a) It will turn 20% faster.
b) The cooling will increase dramatically.
c) The load's horsepower requirement will increase, possibly dramatically.
d) The V/f will drop which will not cause a current draw increase.
You should discuss what the load will do when sped up 20% with someone knowledgeable with that type of load. (Forum members are very knowledgeable in this aspect!)
If the load can take the speed increase then run the load and promptly check the motor's current draw. If it is under the FLA you should have no other problems.
Dave, That's a nice vise! Usually that overall style has the exposed screw. That one has the Machinist's vise slide...
On your ratchet: how many teeth? That isn't what is usually associated with RHFT.

Nice find, Bluebolt.
I haven't posted in this thread in a while but today i was finally able to get out and hit some sales. This is the result of 3 sales on the same cul de sac.
Craftsman vise
Jorgensen miter clamp, NIB
handful of Purdy paint brushes
1939 Snap on Socket Wrench box set, complete with original decal. 5.00
Plomb wrench and socket
Snap on Ferret 3/8" ext
NYE pipe wrench, never seen that brand before
Craftsman combo wrench
screw extractor
old RPM gauge
Boot rack, on top of Jorgensen clamp, for rubber waders/boots
The snap on stuff came from a 90 year old lady that was getting rid of tons of neat stuff. The kit is in near mint condition! She also had old watches and a matched pair of Gillette TTO Fatboy razors, like new from the 60's.
I have been busy with other stuff but yes I have picked up a few scores lately. And today I found something that Beatcad does recently!
Spent two hours catching up on this thread time to go unload todays finds!

Just to tease Nine4GMC LOL.
Delta grinder stand and Craftsman table saw stand.

more finds.
From the same sale as the gerstner
hein warner "rescue kit" porta power, the pump seems to be working, good enough for the price i paid.
Vintage craftsman pipe wrench, plomb adjustable wrench, snap on flex allen driver probably for carburetor adjusting, chicago mfg plumbing adjustable wrench and cal hawk trim tool.
Estate sales finds that got mixed together lol. 1960s tonka hook and ladder fire truck, union carbide 6-12 "banned" insect repellent, 3-1 and wd-40, 2 usa lazy susan turntables, new air chisels in a 1945 ammunition pouch, klein diagonal cutting pliers, bruno circle cutter, walden spin tite nut divers, craftsman socket rack, sears taiwan metric and craftsman usa sae impact sockets, craftsman complete tap and die set, snap on 1 1/2" crowsfoot, craftsman vintage glue sticks and crown label staples and craftsman wrench racks. Oh and a pennzoil made in usa counter stool.
Yard sale coca cola, stp and other patches, can full of large ball bearings, craftsman vintage soldering iron and two complete sets of millers falls a-z letter stamps in different sizes.
Total outlay for the day was way over my limit with the gerstner box purchase at about $400 total.

Nine, are you picking out of my garage when I'm not looking? I have (had?) 2 of the Holley fender protectors: bought them new back in the day. Also the Tape dispenser, (great for 1" masking tape) and of course the Proto wrenches...![]()

Baldor 1/2HP 7" Grinder - rough ($20):
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Mystery machine - it presses and heats up to 550 degrees. It might make a great hamburger ($5):
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Trio of Master Heat Guns (one is DOA) ($12):
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Everyone's hitting it big this weekend!


Well Bluebolt, since you aren't sure what all these are for, I be happy to take the assorted C clamps you have from 1" to looks like 6" off your hands, and those two tack hammers with the rounded ends, - don't know how those ever got past QC. also the specialized non-adjustable gear puller in pic 5...
I know what you mean about "over the limit" the past few weeks has been almost "normal" where I've averaged around $20 a week or so. My overall average had climbed the last year or so to nearly $50 (From some large buys of complete tool boxes, and a few high dollar tools), and now its tapering off under $40. This is over about a three year period.