Press and hammer owners, repeated on and off sessions can fry your motor.

Dan Seaver

Dan Seaver

Joined
Jun 25, 2007
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898
Well after watching some videos and seeing this done a lot, I thought someone needed to post about it.

I know that you want to turn your hammer or press off between heats to save electricity and cut down on noise. The problem with that is when you start the motor it takes a lot more energy and that extra energy puts wear and tear on the motor.

I'm not saying that you will ruin your motor tomorrow by doing this but what is more expensive; $4 more electricity for an 8 hour day or a new $500 motor.

I'm only posting this because I have done it myself and trust me, that $4 is a hell of a lot cheaper. :o I still turn my hammer off but only when it will take 30 min or more for the billet/bar to heat up.

-Dan
 
Dan, that's one of the reasons I wear earplugs! It runs for long periods of time. With my motor mounted overhead, it really makes for some annoying noise!
Mike hammers ma about it too. Everytime he sees a picture of me not using them , I hear about it (BOG) Thanks for friends who look out for ya!
 
If you save $4 per day, you'd have to be burning through two motors a year to make it worth running continuously. You'd save $1440 in electricity per year turning the machine off.

It's likely the savings per day is not that much. It would take some effort to find out for sure, though.
 
Yea Bruce, I find myself walking around the lawn and into the house with my hearing protection on because I'm so used to having it on I forget about it. :o

Its a good thing I don't have any neighbors or they would think I'm crazy. :p

Phillip, I'm not sure about exact savings. My hammer uses $6 for an 8 hour day but I'm not sure how many extra KW it uses when starting. If your working 40 hour weeks at the forge I could easily see you burning though two motors a year.
 
I have very few neighbors and those nearby will confirm the fact :-)
i like preserving my hearing for turkey hunting.
 
It would be interesting to find out for sure.

It's possible that repeatedly turning the motor on/off would actually cost more money in electricity. (to charge the coils)
 
I see there is such a thing as a programable variable frequency drive, with a
setting for a soft start. Might be the way to go if you are running a 3 phase motor
on single phase.
 
Had my first 5hp on my 100lb power hammer die on me last summer. Picked up the motor used with the hammer 15yrs earlier. Replaced it with a new 5hp 3ph with a static inverter. The motor cost me $200 delivered. The press came with a 5hp 220 single phase used. Been running it for almost 10yrs now. The hammer has a clutch that heats up if I let it run so I always shut it down between heats. The press is just to noisy even with Hearing Protection. So I shut that down too unless I have multiples in the forge. So far it has cost me $200 to replace one motor. I guess the motor nymphs live in my shop.
 
What type and HP of motors?

We have polishing machines that we use greaseless compound polishing wheels on and to dress the wheels (applying compound) you hold the tube of compound with one hand and fairly forcefully apply it to the wheel while cycling the motor on and off. The reason for this is the compound (not sure if you're familiar with it) gets liquified by the friction and spreads onto the wheel as you rub it in so you cannot let the motor rev up or your compound will fly off. This could be done 10 to 20 times a day, every day for years on end and out of the 5 machines we have that are used for these wheels I've only ever seen one motor replaced in nearly 20 years (and that was because somebody decided to blow the innards out while the motor was running and you could see the sparks blowing around inside the motor). I believe all the motors are 5 HP 220V 3 ph.
 
Dang, maybe bad motor luck just runs on my road. The farm has lost a 3 hp single phase, a 3hp 3 phase, and about 6 other motors this year and my hammer motor went kaput a month after I had my hammer running after a day of lots of on and off. Everyone I talked to figured it was the starting and stopping. Its also possible that newer motors don't suffer this problem as much; I don't know just trying to warn others from the problems I've experienced.

69 I don't think that is as bad as letting the motor stop then restart it since it doesn't require as much energy.

Phillip, I wonder if there is a way to find out how many watts a motor draws when it starts. Would be interesting to find out.
 
My hammer runs continuous while I'm forging, no noise when not hammering.

I shut the press off when not pressing, is too loud.

Both have 5 hp Lessons and both 10+ years old. Only had to replace a starting capacitor on the hammer motor.
 
Dan Seaver said:
69 I don't think that is as bad as letting the motor stop then restart it since it doesn't require as much energy.

Phillip, I wonder if there is a way to find out how many watts a motor draws when it starts. Would be interesting to find out.
Click to expand...

Actually, there is quite a bit of stopping involved with the application of compound, as it gets too hot and liquid you have to stop and let it cool for a few seconds then go at it again and you're applying enough pressure to slow or even stall a 5 HP motor esp. when doing a larger wheel (12" - 14"). I recorded a video while I was doing some polishing once and there's some film of me dressing a wheel but I never posted any of it. maybe I'll see if I can find it and post it up on youtube.
 
I pretty much do the same as Don. I have yet to replace a motor or starter. the press is running a three phase motor with a magnetic starter and like he said the hammer dosen't make enough noise to be heard over the forge unless I'm pounding something.

But it is true that the most wear/current draw occurs on startup of an electric motor. for instance if you were to look up the specs of a five horse sigle phase motor running on 120 volts the plate claims that it draws something like 18-20 amps under full load at startup it is not unusual for that same motor to draw up to twenty percent more amps or up to 24 amps. on the other hand that same motor while idling with little or no load like when the hammer id idling will only draw three to five amps. if it were running on 220 volts the amperage would only be half but the heat or watts generated would remain the same so start up cost would also remain the same.
 
Dan Seaver said:
Dang, maybe bad motor luck just runs on my road. The farm has lost a 3 hp single phase, a 3hp 3 phase, and about 6 other motors this year and my hammer motor went kaput a month after I had my hammer running after a day of lots of on and off. Everyone I talked to figured it was the starting and stopping.
Click to expand...

Sounds like under voltage or dirty power to me. Are you near the end of a distribution branch?

You may need a line conditioner if you're burning that many motors. That's just not a normal situation.

Do you have a voltmeter? Have you checked the average line voltage?
 
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