Motor questions for 10”x15” C&P

1.5 hp will be fine. I’m guessing you’ll be running it on 220v, so make sure you have an adequate power supply.

There’s a good chance your motor runs at 1725rpm. Varying the motor pulley size will indeed vary the speed at which the press will run. Are you planning to run the press by connecting the motor to the flywheel? The drive pulley size (whether that’s the flywheel or a right side pulley) will play a role in determining the speed at which the press will run.

I believe the 10x15 C&P requires six flywheel revolutions per impression. If you’re running a 1725 motor with a 2” motor pulley to a 36” flywheel you’d end up in the neighborhood of 16 impressions per minute. That should be a very safe speed and, depending on the motor shaft, you may be able to find an even smaller pulley.

Chances of finding a used frequency controller are pretty slim. They’re out there, but they’re still rather pricey—especially when you get over 1hp. For now I’d recommend sticking with the setup mentioned above. Just find a cheap A style vbelt (might have to buy it online) and a suitable variable stepped v belt pulley (which will be cheaper than the flat pulley you’ve got in mind). The belt will probably run you about 10-15 dollars and the pulley should be about the same.

Hope that helps. If you need more advice please let me know.

Regards,
Brad.

Thanks Brad!
I was planning to use the right side pulley on the press - not the flywheel. I’ve not seen one hooked up to the flywheel before.
What is the benefit of the V belt vs. the flat belt?

-Rebecca

V belts are, in my experience, cheaper and easier to find. Same with v belt pulleys.

I would concur — I just motorized my 10 x 15 NS using an old Kimble motor and flat belt, and the belt was about $10.00/ foot and I needed about 10 feet. Also, you would have to get belt lacing for a flat belt. Other advantages are that that v-belts are a bit more forgiving in terms of alignment, and can turn a smaller radius, which will allow a slower speed if need be. You could also get a cone pulley which would allow you change speeds fairly easily. Remember that if you use the belt sheave on the right of the press your impressions per minute will increase — it’s only 24 inches in diameter.

Hey folks… thought I’d jump in… I’m actually a friend giving Rebecca a hand with her motor issue. My background is furniture making, and I know some about motors and pulleys. Here’s my question… I’m surprised to hear about using a vee belt on a flat pulley or over a flywheel, since I always thought the transmission of power occurred mostly over the tapered sides of a vee belt…. but it sounds like you guys are saying a vee belt will work okay over a flat pulley (or flywheel). I’m just surprised there isn’t slipping, or that the small surface area of the point of the vee belt is sufficient.

I’m assuming also that the crowning on the press’s big pulley (you called it the belt sheave?) would be enough to keep the belt tracking straight.

My idea had been to use this big, old 1.5 hp /1725 rpm/115 volt DC motor I have, and attach a voltage regulating switch to create a speed control (like a sewing machine pedal). But, it may be easier to just get ahold of a cone pulley, and use one of the other old motors I have lying around, and then just come up with an easy way of maintaining the belt tension.

thanks for the feedback,

noah

Noah,

I was skeptical too, but I’ve been running a v belt on a flat pulley for some time and have never had an issue. You’d be amazed at how little effort these press pulleys require to keep turning—you’ll want to give the flywheel a shove before you flip the switch to start the motor though. Big, old motors are handy… if only because of their weight. I use a newer 1/2hp 1725rpm 115v motor on my 10x15 and, bolted down, it is fine.

Keep in mind as well that the flywheel should be turning away from the press operator.

Hope this helps.

Brad.

The surface area of the v-belt may be small against a flat suface, but in contact with a large diameter flywheel or drive pulley there are many running inches of contact. One usually has to start the movement by hand before engaging the motor, but after that it is a consistant pull; it is when starting from a dead stop that a v-belt will likely jump off a flat flywheel or pulley. Use a small diameter v-pulley on the motor.

thanks… got everything ready -a big belt, misc. pulleys, misc. smaller belts… an extra arbor in case I need to step down even further…. will give it a shot tomorrow morning.

cheers,

noah

Everyone seems to forget that the motor is DC. Where will you get the direct current to drive the motor. Most areas have AC or alternating current available.

Dick Niehaus

thanks again for the feedback folks. We managed to get the press running with the extra AC motor I had and some random parts, pulleys, an old grinder arbor, etc. We got it stepped down to just about 16 impressions/min.

Re: Dick’s comment… yeah.. the first motor I was going to try to use was a big ‘ole, 100 lb. DC motor. It’s rated at 115 volts, and it runs okay (from what I could see) wired up to normal household current. I’m dangerously ignorant about the consequences of running a DC motor like that on AC current long term, but using a normal light dimmer switch as a test, we could vary the speed of the motor (something you couldn’t do with a normal AC motor). I just thought it would’ve been cool to be able to speed and slow the press at will without any belt changing or a transmission… couldn’t resist the tinkering. Anyway, I suppose I’ll save any more of this for an electric motor forum.

Suffice it to say, we just went with a smaller AC motor, wired up the switch, and it seems to work fine.

And, the vee belt works great on the flat pulley. The machinery restorer in me shakes his head, but the presswoman at hand is pleased.

Cheers,

noah.

Noah is a wonderful gem who set this up for me, even though he was suffering from a terrible cold. Here are the pictures. I’m so excited!

letterpress_motor1.jpg

letterpress_motor4.jpg

letterpress_motor2.jpg