Making Belt Grinder need help

Well I suppose you could do that. Don't know how well it would work. Wayne Goaddard made the drive wheel on his belt sander by glueing rubber to the wheel, one of the chem companies said he could not do it but he did. If you wanted to try it, do some research on rubber in the 60 to 80 durometer range and what type of glue you would need to attach it to the wheel. I would be very carefull at 3600rpm though, it may just fly off. If at all possible see what it may take to get that wheel off. It may be easier than it looks. It may be LH threads too can't tell from the pics. I had one with threads on it and it just needed a little help and it came right off. Whatever you do don't mess up the good end of the shaft by grabbing it with vise grips or the like. It's all up to what you want to put into it. 3600 rpm is very fast for most applications in grinding. Slowing it down will be your best bet. Even if you cut it in half as you stated, it would work much better. The motor looks really cool and seems to have more power than you need. Just need to tweek it in to get the best performance out of it. It can be a gradual process so go at your own pace. I have been collecting knife making stuff for 15 years now and I still have a bunch of toys (er) tools i want to pick up. Looking forward to updates as you go along.

Chuck
 
Hello TJ

Check the voltage on the output of your rectifier with your meter set to DC then check it again with it set to AC. 110 Vac into a full wave rectifier feeding one capacitor should give 155 Vdc. 110 Vac into a full wave rectifier with two filter caps in series and the center point of the caps grounded will give 310 Vdc. Some of the equipment that I work on use supplies like this. Check to see if your meter is a "true RMS" type. If it is not, you will NOT get the proper readings with these types of waveforms.

You will need to use something like a 5600 microfarad capacitor to reduce the ripple to about 10 Vpk-pk. A 1000 microfarad capacitor will give you about 58 Vpk-pk of ripple, a pretty big percentage of the 155 Vdc.

ripple voltage = current / (2 * frequency * capacitance)

10.4 Vpk-pk = 7 A / (2 * 60 Hz * 0.0056 Farads)


For safety, mount your rectifier and capacitor in a METAL box with at least 3/8 inch clearance from any of the terminals on the rectifier and capacitor to the sides of the box. These are the rules that are commonly used when designing electrical equipment powered from a 110 Vac supply.

Your 35 Amp rectifier is probably a metal block that is about 1 to 1.5 inches square and about 0.25 to 0.5 inches thick with a hole in the middle. It will dissipate about 10 to 12 Watts when your motor is drawing 7 Amps so you will need to mount it on the side of the box so that the box can act as a heatsink. Otherwise, it will lead a rather short life.

The photo of the label on your motor is not very clear but it seems to read 2.5 hp, 130 Varm, 14 Aarm. The starting surge current of the motor is related to the mechanical inertia of the whole mechanical system. With no extra load connected to the shaft, you will get a starting surge current that is several times the rated current (14 Amps). This is why you saw the lights dimming when the motor started. It would be best if you can remove the flywheel/pulley from the shaft of your motor. When you add the disk, the disk will add inertia. If you do not, you may start blowing breakers in your house. A 15 Amp, 110 Vac circuit is already marginal for running a 2 hp motor WITH a motor drive to limit the starting surge current.

Phil

Phil
 
thank you Chuck

those are excellent pictures....
and i love that 1inch disc..... man, that is heavy duty.. !!
- where bouts do they sell those discs?

thanks again
Greg
 
well the rectifyer puts out 110 volts that whot my meter reads but when its running the motor it reads 150. is this ok, am i going to damage the motor.

also its 18 A.ARM not 14 A.ARM what doe these numbers mean. are thay the running amps on the armture.

Do you think i need to get a diffrent cap? and do you realy think this motor puts out 2.5 hp?

does any one know how i can get the flyweel off this beast
here is the photos of the motor in its movable mounting.


motorandmount.jpg

motorandmount2.jpg

motorandmount3.jpg

motorandmount4.jpg
 
well here is one way...... probably not the best way.... you could alway clamp a pipe wrench to that shaft sticking out the back... and similarily clamp a pipe wrech to the nubb on the front..... as for which way to turn...??... i would think it would loosen the opposite way of rotation.. ? (maybe )

-- remember..... that doing this may bugger up the end of the shaft and the front wheel... so you probably won't have the option to put a disc on the back end.... pipewrenches are notorious for nibbling up the surface

if its hard to come loose...... remember to put a long pipe on the ends of the wrench handles.... this will give you much more torque

is that a lock nut i see in the center of the flywheel ??

take care
i hope it turns out..
Greg
 
JT

If you don't have a capacitor connected to the output of your rectifier, the meter may read something like 110 Vdc, depending on whether your meter is a true-RMs type or not. See what it reads with a capacitor connected, with and without the motor connected. It would be helpful if you posted a better picture of the label on the motor.

You should really connect a circuit breaker in series with your power cord, before the rectifier. Something like either of the following would do:

http://www.surpluscenter.com/item.asp?UID=2006061412280978&item=11-2551-C&catname=electric
http://www.surpluscenter.com/item.asp?UID=2006061412280978&item=11-2555-C&catname=electric

You would have to check with the motor manufacturer to see if 150 V will damage it.

From the first picture in your first post and the second picture of your last post, it looks like there may be a screw that goes into the end of the shaft to hold the flywheel on. It appears that the screw is either an allen key or Torx type.

Phil
 
wll that think you see in the center is just the tip of the threded shaft it has a little hole in the center of it that goes in about 1/4 inch. i tryed the pipe rench thing but it just slips on the shaft it has a little bit of marks not but i turned on the motor and jsed a fine file to remove them. i realy dont know what to do.

about the speed control i had an idea.

speed controler.jpg



conect like 2, 3, or 4 caps in series to the incoming 150 volts. then tap off each cap at the voltage you want. beacuse say 5 caps conected in series has a total voltage of the 150 but if you say conect the positive of the motor to say the positive if the third cap from the - incoming voltage you sould have 90 volts. because each cap has 1/5 of the total 150 volts. this should work and be cheep to make. let me know what you think
 
ok i feal likw a dumb ass now, the last post i did would work but once the caps discharge it will not charge back up unless all the caps discharge and tha all recharge at once. sorry
 
TJ

Take some time and have a really good look at the end of the shaft with the flywheel on it. That "little hole in the center of it that goes in about 1/4 inch" is probably a screw. Try putting an allen key or torx driver in it while holding the flywheel.

You are correct, the circuit with the five caps in series will not work. Your motor wants to be fed DC. Caps don't pass much DC.

The dimmer might work. Just be aware that you probably won't be able to get full power out of your motor and that you are likely to fry the dimmer if you load the motor heavily. The light dimmers sold at the home improvement centers are built down to a price and probably won't be very tollerant of abuse. The triacs used will have a maximum current carrying capacity, so just mounting the dimmer on a bigger heatsink will not really increase the capacity of the dimmer by much. It takes 746 W of electrical power to make 1 hp, assuming that your motor is 100% efficient. Higher powered light dimmers are used in theatres but are probably going to approach the price of a proper DC controller for your motor. The post you have found is from over a year ago and there is no indication that the dimmer is still working.

In view of your limited budget, your most sure way of getting a good, reliable result is still to get some step pulleys on an auxilary shaft held by some pillow blocks. Ron Frink sells them all (www.beaumontmetalworks.com). Remember, it will cost you time and money to experiment.

If you really want to control the speed electrically, try connecting a full-wave bridge rectifier (like the one that you already have) and a half-wave rectifier to your AC input. Do not connect a smoothing cap across the motor. Use a switch to connect your motor to the output of the full-wave bridge to get "full speed" and to the half-wave rectifier to get "half-speed". Make sure that the rectifiers are all good for at least 30 Amps and mount each of them on a separate heatsink.

Phil
 
Greg Obach said:
thank you Chuck

those are excellent pictures....
and i love that 1inch disc..... man, that is heavy duty.. !!
- where bouts do they sell those discs?

thanks again
Greg
Click to expand...


Greg.

I made that disc. Started with a 4 inch thick piece of 10 inch dia 1040 steel. Made about 25 pounds of chip and that was the result. It does run smooth. If I had it balanced it would be even better. I had to press it on the motor shaft so getting it off will be a bear. I have 2 more motors that i want to put discs on but need to make another disc or 2. Just have not got the time.

Chuck
 
JT.

Are the threads on thenoseof the pully right or left hand? Ive been trying to see but my eyes really suck right now. Been doing a lot of close work. Also could you take a really close picture of the end of the shaft with the pully on it? Do you own or have access to an oxy acetylene outfit? If there is no set screw in the hole then it may be locktite holding that thing so tight. Warm up the center of the shaft. It may break loose. Since you've already used a pipe wrench on the short side try wrapping some leather aroud the shaft first then put the pipe wrench on it. Another thing you could do is get the numbers off the motor and look up the parent companies web site. Many times they will have a breakdown of the motor and be able to tell if those threads on the shaft are right or left hand. Seen them both ways and since the motor can turn in either direction there is no way of readily telling. When you worked for Nordic Track do you remember how the motor was mounted? This may give us a clue also. Keep trying the results will be worth it.

Chuck
 
OK. Took some close up looks at the motor and label. It was wired for CCW rotation and the nose threads appear to be arh so i would assume the shaft threads are also. If you need a bit more torque on the 5/8 shaft try making some sort of bushing with a key to go over the shaft. If you can find one you can bugger up the surface of the bushing all you want and it won't hurt the shaft. A pipe wrench on the short shaft side (protect the surface) and one on the threaded nose should be more than enough the get the wheel off. If you need to warm up the threaded shaft a bit it may help.

Chuck
 
what if i was the dril a holl through the shaft on the other end and put a bar through it, would that work. also i have been thinking, do i realy need to get it off. because once i do where do i get a disk that will thred onto that type of shaft. I was thinking about getting a 1 foot by 1 foot piece of like plerey glass that is 1 - 1 1/2" thick and cut a hole in the center so that it will fit over the small pulley then cut it into a 9" disk so that i use the steel flywheel for weight to keep the tork up while gringing. the onley question is the plexy glass going to get to hot while grinding. and not i dont know any one with a torch, i do have a heat gun at work that might do the trick.
 
ok this is what i have done sofar, switch turnes on the ac to the rectfyer which then as dc goes to the plug where the motor and volt metter is connected. the nice thing about haveng dc to the plug is the i can change the spinn direction by pulling the plug out and turning it around. here is the pictures
DSC001951.jpg

DSC00201.jpg

DSC00202.jpg

DSC00203.jpg
 
DOn't mess upthe good end of the shaft. If all else fails just put the disc on the exposed shaft. Don't think plexigalss will hold up. You could get tsome thick Micarta but that would be expensive. If you can't easily get the flywheel off then just leave it and mount the other side. This will get you up and running with the least expense.

Chuck
 
I tryed the half-wave rectifier idea and it did read 53 volts on my meter but once i counected the motor it read 120 but cuickley went up to around 150. not i did notice that the motor had a hum that it did not have befor and also it seamed to not start as smooth and when using the full-wave rectifier. also i did notice that if i tryed to stop the flywheel with my hands the voltage on my meter would dropdown to around 100-120, this does not happed with the full-wave rectifier. I do not like the half-wave rectifier it seames like its running bumpy like in pulses which is true sience its using dc voltage that is coming from a half-wave rectifier. speed was allmost the same not a big diffrence. what is going on and why is it reading 150 with a half-wave rectifier connected to the motor, but just by its self reads around 53

i did find this speed controller i thin would work.
http://home.maine.rr.com/randylinscott/aug99.htm
 
I got the flywheel off. i barowed a pipe wrench from a frend and studyed the thred so as i would turn it the right way, it came off on the first try. here are the pictures of it.
off2.jpg

off3.jpg

off4.jpg

off5.jpg

off6.jpg
 
There you go. Now you have room to play. What is the dia of the flywheel?? It looks like you could almost bolt a plate right the the face. But then you have to deal with the screw when you reverse. Well at least you have a clean slate to start from now. You could cut off the threads and just use the shaft. If you buy a disc you can drill a dimple in the shaft to stop the set screw or have a key way milled into it. Either way I think you will be happier. Good on ya and get a grindin.

Chuck
 
ya i was thinking about bolting a plate on as well. i was also thinking about mounting the flywhele backwords and drilling a hole allthe way through the small part of the flywheel and shaft and put a small bolt with a lock washer and nut to keep it from spining off.
 
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