Milling machine needs more power!

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
thanks for the help everyone!

poobah,

ok, i understand motor start caps now. changing their values wont help me out. the clutch is a decent idea, but probably too expensive, since i have other options in that price range (VFD's).

ill try a rope and some clever engineering to see if i can get it to start that way.

Schaef,

it is a bit different than a drill press. the spindle and head on a milling machine is pretty massive, even on my small one. its quite heavy and take a bit of force to start it moving. when i arrange the belts for the top speed, its difficult to turn the motor by hand. but once you get it going, its pretty smooth. its just the initial inertia that takes the power.

at lower speeds, it does the same thing. it dims the lights when it starts and starts slow, but after a second, its at full speed and almost nothing will slow it down. it will kick off the piece you are drilling/milling before it stalls. ive never seen it stall, but its broken bits before.

burnedfingers

its a harbor freight. also made by grizzly, enco, jet, and a few others. its the 33686 by HF. here is a link:

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=33686

mine has a 2HP motor (1.5KW) instead of the 1.5HP one listed. its stock and came with it, i bought it new. its much smaller than the ones you are probably familiar with... i dont have an amp clamp, its just on my meter. i could wire it up some how to see how much power its drawing when running though.

i COULD have the belts tensioned too tightly though. i might try and loosen them a bit and see what happens.

chipco3434,

thats a good idea, i forgot about VFD's. i did a quick check on ebay, and a 2HP model would run me $100-$250 depending on how lucky i was with bidding... thats not TOO bad. im kinda running thin on money right now with going back to school and dont need to be buying things, but if it comes to that, it would be the best solution presented.

can you use an AC variable drive with an induction type motor? if so, that would be something to definately add down the road. i would always use the mill on fastest speed, and use the VFD to adjust the speed electronically.

plus, my CNC software allows me to control a VFD through its program.

ill have to check with a local motor shop. however, i feel they will give me the same answer i was initially given here "move" or "upgrade your electrical outlet". ive known tons of people using these machines without a problem on 15amp circuits at all speeds, so im not sure why im having problems. maybe its because i got the "upgraded" 2HP motor, which draws more juice.

EC8010

i thought about this. but my shop is heated for the most part. its certainly not cold, its just a bit cooler than the rest of the house. plus, his happens in the summer time, OR, when ive been running the machine for a few hours. it always happens. and, there is no gearbox for this one. its a motor with a pulley, that goes to an intermediate pulley, then to the spindle pulley.

i might try this one too... Schaef mentioned that the pulleys might be too tight. there are 2 ways to tension the belts. the motor sits on a swivel bracket and swings in and out to tension the belts to it. the middle pulley is on a swivel as well and tensions itself to the other two belts. maybe i could start the motor, and slowly tension the belts, kinda like a limited slip clutch? the motor on its own starts pretty quickly. but then, once its running full speed, i could slowly engage the belts (my hands would be away from the belts, the tensioning is done away from them), and see if that works... its a bit of a hassle, but until i can buy the VFD, its a decent option i think...

edit:

all the VFD's im looking at need a 220vac input, so that wont be an option now...
 
[EDIT: sorry didn't read the tail end of your post!]


You know,

The clutches I'm talking about should not set you back that much...

But there is yet another way to start this on high speed. The motor, or the third pulley, is on a pivot or slide so you can loosen the belt... just loosen the belt so the motor can spin up without load, then crank the adjuster tight. This WILL burn your belts a little, but who cares? Belts are cheap!
 
I may be blind, but I have not seen the obvious stated.

Check the motor name-plate. It should have the rated voltage and rated current stated.

If it is a 220v motor, it will not like starting on 110v, and may well overheat while running. Motors do not like being run below their rated voltage.

If a 110v motor, the rated full load current is about 13 amp, and (if under load), it can draw about 6 times that on startup for a very short period until it starts turning. The voltage drop will be very high, your outlet will be overloaded, the motor will not start, and your breaker will trip.
 
poobah said:
[EDIT: sorry didn't read the tail end of your post!]


You know,

The clutches I'm talking about should not set you back that much...

But there is yet another way to start this on high speed. The motor, or the third pulley, is on a pivot or slide so you can loosen the belt... just loosen the belt so the motor can spin up without load, then crank the adjuster tight. This WILL burn your belts a little, but who cares? Belts are cheap!

yeah, belts are very cheap indeed! i was even thinking about throwing one of my extra geared motors on a worm drive that i could control the tension. so it would be an automatic belt tensioner when it starts up...

ill try starting it like that and see what happens.

edit:

what kinda price are you talking on those clutch thingies?


rjb said:
I may be blind, but I have not seen the obvious stated.

Check the motor name-plate. It should have the rated voltage and rated current stated.

If it is a 220v motor, it will not like starting on 110v, and may well overheat while running. Motors do not like being run below their rated voltage.

If a 110v motor, the rated full load current is about 13 amp, and (if under load), it can draw about 6 times that on startup for a very short period until it starts turning. The voltage drop will be very high, your outlet will be overloaded, the motor will not start, and your breaker will trip.

i believe its a 110 motor, ill take a picture of the back plate of it, it has a lot of information on it...
 
burnedfingers said:
quote:

i COULD have the belts tensioned too tightly though. i might try and loosen them a bit and see what happens.

Does it have V belts or cog belts?

Its a little fellow but still very nice and handy to have. What I wouldn't give to have one in the garage.

as soon as im finished eating lunch, ill go down there and play around a bit. i looked and im only running at 820rpm. the top end is 2500. so, im way below the top. i think im only in the middle of the spectrum. no wonder i get such rough milling cuts!

its got v-belts. i plan to change it to those belts you use for table saws that reduce vibration. i cant remember what they are called, but rockler or nice woodworking shops have them for cheap.

hehe, it may be little for a milling machine, but its still big and heavy! with the stand, its just shy of 1/2 ton. and when the head is not all the way down, its taller than me. with the head all the way up, i cant reach the very top to change belts.
 
I'm assuming of course a 110v outlet.

If a 220v motor, uprate your outlet.

If a 110v motor do not uprate your outlet to 220v, (unless of course the motor can be wired for 220v). You will destroy your motor.

The cheapest option is a soft starter. There are a number of types, the modern ones are electronic of course. These basically reduce the motor voltage (and hence current drawn) on startup, then ramp it up slowly as the motor starts to spin. Once up to speed they switch out of circuit.

They work best with loads that are mainly inertial to start with, as yours appears to be. The energy required to start the motor is basically spread over a longer time, so that the large start current, (and hence excessive voltage drop you probably have at present) does not occur. No modification is required to the motor.

Find a local supplier, and check for size, costs etc. He may be even able to loan you one for trial, or sell you a second hand one.

Don't bother with Variable Frequency drives. They incorporate a soft starter, but are much more expensive. A UPS for this size , (remember the high start current), would be large and expensive too.
 
haha, this is funny. after 3 pages, it was the simplest solution that worked. i had the belts too tight. now, i didnt have them TIGHT, they were just snug. the one to the motor was a little loose, i could pinch the belt together in the middle, but the one going to the spindle was tighter and i couldnt pinch it together.

i tried the idea where i loosened the motor, turned it on, and slowly tensioned the belts. it worked fine. i played with the belts by hand a bit and noticed that it was a LOT easier to move the spindle by hand now, even at the highest RPM. so, i just flicked the switch, and it worked. the belts could be a BIT tighter, because i smelled rubber when it was turned on, so there was some slipping. but right now, they are VERY loose. but, it turns on and doesnt dim the lights all that much at all.

woohoo! anyways, here are the pictures anyways, who knows if someone else will have a similar problem.

An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.
 
rjon17469 said:
Also, assuming I'm reading the information correctly, your mill is rated for 17 amps on 110 volt circuits. So when under full load, it could be expected to throw a 15 amp breaker.

yeah, its peak current looks to be 17amps. so, it will trip the breaker if fully loaded. maybe its a design feature that will trip the breaker if it stalls out, or hits a heavy load, and wont burn itself up...

so where in illinois are you located? i grew up in springfield area.
 
cowanrg said:


yeah, its peak current looks to be 17amps. so, it will trip the breaker if fully loaded. maybe its a design feature that will trip the breaker if it stalls out, or hits a heavy load, and wont burn itself up...

so where in illinois are you located? i grew up in springfield area.


Could be, but I'm betting it's designed to be used with 20 amp circuits.

That's funny. I'm actually in Springfield myself right now, although in a week or so I'm heading back to UIUC. Are you still in the Springfield area?
 
RECOMMENDATION...

With those short belts, you should be using a "cut" v-belt. Those standard belts EAT power and makes mucho heat on the small pulleys.

It's the style on the left...
 

Attachments

  • cut v.jpg
    cut v.jpg
    24.3 KB · Views: 85
chipco3434 said:
RECOMMENDATION...

With those short belts, you should be using a "cut" v-belt. Those standard belts EAT power and makes mucho heat on the small pulleys.

It's the style on the left...

upgrading the belts is on my list... i was told that these belts are very good, reducing vibration, increasing power, and dont wear out as quick:

http://www.rockler.com/ecom7/produc...DBDADADADADFGCGFGMHEHDDADADADBDB&filter=belts

any idea where to get the ones you are talking about?
 
cowanrg said:
nope, im out in colorado. i moved out here in '99 to go to college, and have lived here ever since.

what are you doing in springfield? do you have family there? i was just there maybe a week or two ago to visit my family.


Staying with my family here until I gotta go back. I'll be moving out soon enough though. Still gotta figure out where though.:smash:
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.