Question on Motor Amperage

Cue Crazy

Cue Crazy

AzB Silver Member
Silver Member
Wonder if anyone can help me out and make sure I have this correct. Say I want to use a switchable supply with a 12v gear motor to alternate the rpm range. Do I have this correct, that the supply needs to be a higher amp then the highest amperage the motor is rated at? So say the motor is 3amp at 12v, and 173rpm, does this mean I just need a 12v supply that has more the 3 amps? That's just an example, I'm keeping in mind that if the motor pulls more amps at a lower voltage & rpm, then whatever is the highest amp the motor is rated at would be My mark to go on when purchasing the power supply.

The reason I ask is because I've been researching cheap alternatives for a power supply, and well I would just go with say a 15amp supply to be safe, but the higher the amp the more they cost, and for what I'm using It for that would be a waste of extra money If I only need something in the 5-6amp range to cover the motor.

Thanks,
Greg
 
Hi Greg,
If your mtr. draws 5 to 6 amps you could go with an 8 to 10 amp pwr. supply and put a 7 to 8 amp fuse btwn the supply & the mtr. As long as you never over-load the mtr., you should never blow the fuse. If the mtr. does see a load it will blow the fuse thereby protecting the mtr. & the supply.

Since you mentioned 12V. I'm guessing you mean DC voltage. You also mentioned gear-mtr. and if it's drawing 5 to 6 amp, it's going to be a torquey little SOB at 173 RPM. If I were to guess once more that this is for a spray booth lathe you should be very good to go. Just try to keep the mtr. & pwr. supply cool as they will be seeing 'continual' use and will generate heat. I'm going to stop guessing now.
 
KJ Cues said:
Hi Greg,
If your mtr. draws 5 to 6 amps you could go with an 8 to 10 amp pwr. supply and put a 7 to 8 amp fuse btwn the supply & the mtr. As long as you never over-load the mtr., you should never blow the fuse. If the mtr. does see a load it will blow the fuse thereby protecting the mtr. & the supply.

Since you mentioned 12V. I'm guessing you mean DC voltage. You also mentioned gear-mtr. and if it's drawing 5 to 6 amp, it's going to be a torquey little SOB at 173 RPM. If I were to guess once more that this is for a spray booth lathe you should be very good to go. Just try to keep the mtr. & pwr. supply cool as they will be seeing 'continual' use and will generate heat. I'm going to stop guessing now.
Click to expand...




Thanks KJ, and yes You would be correct, It is for a spinner I'm working on. It will be turning 4-5 cues at a time. I Think I already have My spindles figured out, and have those mocked up with the bearings, just waiting on some belts to start assembling It. I may switch over to sprockets, but I'm trying some comercial hoover belts first.

When I get the setup under power, I will take some pics & share It here.

The motor does sound like It should have some torque, and I do know that they usually do. I will share that also, but for now I'll just say It's not a wiper motor. I think those only run about 73rpm on average.
It is a surpluss motor that can be purchased pretty cheaply though.;) According to what I read, I should also be able to vary the rpm by reducing or increasing the voltage. I think It goes down to about 35rpm at 3v, 1amp, and up to 163rpm at 12v, 3.3amp, so I over estimated by 10 rpm on the high side in My original post, and I'm not sure how accurate the rating is on them, as the rating is at no load I believe. I'm just trying to make sure That I can get in the required 75-100rpm or whatever I need, and still have alittle bit of torque. I can turn one spindle that I mocked up with a small stepper I supplied 5vdc to that only has a spindle that's about the thickness of a finish nail, and It turns freely at a decent rpm, just not torquey enough for all the spindles IMO, It may would turn one or 2 cues easily, and at about the correct rpm though. I've figured out that each belt may cause friction or drag, but I think this motor I'm gonna get will handle all of the spindles with no problems. Main thing is will It throw a belt or will they slip. I'm using 5/16 shafts for My spindles, so if I need to switch to sprockets It would be easy enough. Just trying to save whatever money I can.

Anway after that I have to locate a decent squirelle cage. Trying to find one that doesn't vent through, or have the motor mounted in the mainstream. I may have to pull a favor locally for that though, not only are they alittle expensive, but shipping would be a killer.:(

Thanks Again for the info,

Greg
 
Greg, have you thought of getting a variable speed controller? It switches 110ac to 90vdc & you wire up a rheostat to control the wattage. Then you control the power by turning a knob, and can fine tune the speed to where it works best. I use these on almost all of my machines. I toss the ac motors that come stock & wire up a dc motor & add a variable speed circuit board so I can fine tune the speeds. It's about $100 or less for one of these circuit boards on ebay, and they work friggin great.
 
Variable Speed Controller

I just put a new one, with more amperage, on my GS saw machine and
what a difference. Graingers, PN 4Z527 ($82.00). You have a variable speed plus two pots, one for high speed adj and one for low speed adj.

Bob Flynn
denalicues.com
International Cuemakers Assoc.
 
One thing I've noticed when slowing down a DC motor, sometimes, depending on how the motor is cooled, it may run a bit hot at slow speeds. I've added a small (110VAC) fan in several situations to help this problem.

BTW, I'm with qbuilder, find a cheap motor controller for this application. They often maintain a better torque at low speeds in my experience.

Dave
 
Hey Guys, Thanks for the advice,

Yeah I've have actually been looking at ways to control It. The Ac to Dc kits are nice, and I have considered them for another project. I have found a assembled board kit w/rheostat that is supposed to be able to hold low end torque on gear motors, and It's only about 20 bucks. The thing is It has a DC input, so I would still have to buy a DC supply also, at another 20 bucks or so. That's still about 40 bucks to control the thing, but alittle cheaper, so I may try It out. I was also thinking about hooking a fan up just to give some amount of extra cooling. Sometimes you can find a deal on the AC supplied kits though, so I'm still doing My homework for the right setup. The motor I'm gonna try first only cost $20, so all in all if it works out, I would only have about 60-75 in the motor & controller package if I went with the DC supplied setup. I'm still researching though, and not for sure which way I'm gonna go.


Greg
 
I have a 2 1/2hp 90v DC mtr on my single spindle finish lathe. Talk about overkill. But I always believe it's better to have too much than not enough. I got the mtr. with mounted fan and controller board from Surplus Center about 10 yrs ago for $40. They generally have tread-mill mtrs., now about $40 and controller boards for about $30. You can also get KBC controller boards on eBay for $25/30. Good Luck, KJ
 
Well looks like I'm gonna hold off on brainstorming the controller. I got the belts in today, and couldn't believe how much drag is added with each spindle. Way more then I originally suspected & to much for My taste. I'm sure It would really heat the motor up with that much drag, and the belts are pretty thick. I could maybe mess with the tension or get different belts, to reduce some of It, but I'm just gonna scrap the belt design right now, and cut My losses while they're minimal. So needless to say I'll be going with a sprocket setup.

Here's what I started with, this is just a mock up for testing, please keep that in mind, nothing is cut to lenth, and the pulleys are just something that came on the spindles I'm using, and will be removed. They were originally some kind of conveyer belt spindles or something that I had laying around from an old surpluss purchase. They were 5/16, and happened to fit My bearings almost perfectly, so that there is no play with the 2 bearings mounted in the U channel. Also on the back of the flange bearings, the OD of the bearing was right on 5/8, so I used a 5/8 drill, and they tap into place, and have no movement there either. The spindles work really well, and It's not the bearings dragging as far as I can see, It's all belt stretch and pulley drag that's My issue with them.

Anyhow, Anyone have recomendations on what number of teeth I should get for sprockets? The motor is already on the way, so The specs I mentioned before Is what I will be using for my motor. I was thinking about using #25 chain & sprockets, but not sure how many teeth I need to get to keep the gear ratio so that rpm's end up in the correct range, and will be best for ajusting the speed through the motor control.

Thanks Again, Greg
 

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From here the problem looks like the belts are way too heavy. I'd try thinner, longer belts or even rubber bands before scrapping that setup. As a side note, with so many pulleys, you might want to drive from the middle to transmit more torque to the ends.
 
I'd have to agree, your belts are too thick for this application. Thin flat belts will eat less HP. Look at it this way. As the thicker belt travels around the pulley it's being asked to compress it's inside perimeter and stretch it's outside surface. The core of the belt stays the same. It's robbing the motor of usable power in doing this and the smaller the pulley the more power it requires to move the belt. However, if your motor is 'on the edge' of being powerful enough at this point, you might want to consider either a more powerful drive or less spindles.

I'm going to suggest also that it takes just as much time & effort to load & unload 6 cues at one time as it does loading and unloading 6 cues individually. I don't see the advantage to a multi-spindle finish lathe. It takes approx. 85% less pwr. to drive a single spindle as it does 6. Start removing belts from the spindle furthest away from your drive until you get to a number that your motor will handle comfortably. I don't believe that chain & sprockets will solve your problem.
 
Greg, whats your spindle pully dia.? I may have some thin belts that will work, It's the ones I'm using. I'll send them to you if you can use them.
Dave
 
Thanks guys, Yes, That's exactly what It is, the belts are way to thick, and don't want to conform around the pullies. You can feel the elasticity in the belts when you try to force them around the pullies, and one of them doesn't want to conform to one of the pullies. I thought about trying to soften them up, but I think the belts are just too large like you guys are saying here. There are comercial hoover vac belts, so they are heavy duty. Anyway I have 6 of them, so If any one can use one for something else like running a wrap motor, let me know. They are much stronger then the singer sewing belts.


The reason I'm going with so many KJ, is because I usually build cues in a series of 4 to 5 at a time, and was thinking of trying to step those numbers up. My thinking is less actual spraygun setup & cleanup time, and less waste. I have considered cutting the number of spindles down though. I never really thought about setup, I just figured I'd use how ever many of the spindles I need each time I spray.


Dave, the widest inside diameter of the pullies are somewhere between .180 and .200, They are about the same size of the pulley on a hightower wrap motor if that helps. The only difference are they are tripple pulley setups, and not single. If You have something that You think would work. I'll buy them from you, and give it another try, or If you can just point me to a reasonably priced source, then Please Pm Me with It.:) I did notice that singer sewing belts are smaller & more flexable, therefore have less drag, but they break way to easily for My taste. I have had some brand new out of the box that were split before I even used them. I ended up going to a different belt on My wrap motor because of that. It just a flat belt that I split down the middle with a razor, so I get 2 belts out of one. It actually works on the same pullies even though they are not the correct match. I have yet to have one break though. Those belt may would work with this if I made pullies to fit them, but they don't have the ridges for timing like the cog belts do.


I have thought about going with cog belts If I can get a good enough price. Does anyone have a source for cog pullies with a 5/16 bore? I could turn the spindles to fit, but would rather not if I don't have to. I only have 2 of them and one belt, and the bore on those are way too small. they do have less drag though.

I think I figured out that I could do the sprockets for about 30 bucks, that would include all the sprockets and the chain the run them, so that's why I was considering using them. Maybe they have some drag, I'm not sure, but It's gotta be less than these monster belts I'm trying now:D I didn't know they were that thick when I ordered them.:o

Thanks Again to everyone here that has lended ideas,and those that have Pmed Me about this.:)

Greg
 
Bicycle chain and weave em they spin opposite directions but who cares. Plenty of old bikes everywhere.
 
QUOTE I have thought about going with cog belts If I can get a good enough price. Does anyone have a source for cog pullies with a 5/16 bore? I could turn the spindles to fit, but would rather not if I don't have to. I only have 2 of them and one belt, and the bore on those are way too small. they do have less drag though.
Greg[/QUOTE]

You can get the pulleys and cog belts from Graingers. See attached pics for a conversion from O-rings to cogs on a GS shaft machine. By switching to the cogs the machine performance was improved substantially. Also, you reduce the load on your bearings with the cog belts.

Bob Flynn

GS002.jpg

001jpeg.jpg
 
Cue Crazy said:
Dave, the widest inside diameter of the pullies are somewhere between .180 and .200, They are about the same size of the pulley on a hightower wrap motor if that helps. The only difference are they are tripple pulley setups, and not single. If You have something that You think would work. I'll buy them from you, and give it another try, or If you can just point me to a reasonably priced source, then Please Pm Me with It.:)

Greg
Click to expand...
Here is a pic of the belts that I got off of Ebay, they are .158 thick and about 4" in diameter. They stretch pretty far. I can spare some, so just let me know how many.
65cb_1.jpg
Dave
 
Dave38 said:
Here is a pic of the belts that I got off of Ebay, they are .158 thick and about 4" in diameter. They stretch pretty far. I can spare some, so just let me know how many.
View attachment 63716
Dave
Click to expand...


I'm spaced at about 4-1/2, so those may be just right. 2 or 3 should be enough for me to tell if they will work or not. If You have a paypal account, Pm Me the address and I'll send you some cash to cover the belts and shipping. That's if your sure you can spare them.:)

I really apprietiate it Dave, Thanks Bud,

Greg
 
QMAKER said:
QUOTE I have thought about going with cog belts If I can get a good enough price. Does anyone have a source for cog pullies with a 5/16 bore? I could turn the spindles to fit, but would rather not if I don't have to. I only have 2 of them and one belt, and the bore on those are way too small. they do have less drag though.
Greg
Click to expand...

You can get the pulleys and cog belts from Graingers. See attached pics for a conversion from O-rings to cogs on a GS shaft machine. By switching to the cogs the machine performance was improved substantially. Also, you reduce the load on your bearings with the cog belts.

Bob Flynn

GS002.jpg

001jpeg.jpg
[/QUOTE]



That's a sweet pulley setup You have Bob, Thanks for sharing the pictures:) I have another project in mind that those would be perfect for.

Greg
 
Cue Crazy said:
That's a sweet pulley setup You have Bob, Thanks for sharing the pictures:) I have another project in mind that those would be perfect for.

Greg
Click to expand...
Pizza conveyor?:eek:

Nice setup Bob.
 
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