Please help resurrect this old drill press

Hi everyone. I am trying to convert and old drill press to DC drive. I was given a brand new
PM DC motor 2.80 HP @ 2089 watts 1.75 HP Cont Duty 1305 watts. I then purchased a
PM-30 Icon threadmill power supply on Ebay, and a 5K pot. For control. Installed everything
and it runs ok. Except there is a seven second delay when you throw the switch!!! and you have to
turn the pot. Back to zero to restart if you stop. I mostly want to run at slow speeds for bigger
drill bits. Seven seconds seems like an eternity, and the zero to start is no fun either. They no
doubt had the delay and zero start for safety purposes. Being old and a novice this is way beyond
me. I did try to find a schematic for this board to attach, but had no luck finding such. Can anyone help? Money is an object. The power supplies I have found on ebay cost as much as a drill press.
Unless someone can steer me to a surplus discount store with the proper supply. I would try to modify
the board if I had instructions, or pay someone to do it. All replys will be greatly appreciated.

Thanks Snitz
snitz382@hotmail.com

Motor voltage max should be about 130 VDC. Unfortunately without the schematic it is difficult to say how to modify the circuit to eliminate the safety features for when used on a threadmill. Looking at the motor nameplate does it mention the voltage and current? Knowing the power in watts is nice but knowing the motor nameplate voltage would help.

Ron

How do you know it's 130VDC, is that the standard voltage for all treadmill motors?

I think you should put the treadmill controller back on ebay or return it, if possible. As mentioned above, it's difficult to modify a board don't know the schematic for and it might use a microcontroller which will need replacing with one programmed to remove the safety features you describe but you might as well start from scratch as do that.

I think it's probably best to buy a generic motor controller of the appropriate power rating. The problem then is, converting your mains voltage to 130VDC, if you live in the US, you could just use a bridge rectifier but if you live in Europe you'll need a transformer before the rectifier. The problem then might be that the controller might not like the unfiltered DC from the rectifier but you can't filter it too much because it will increase the RMS delivered to the motor.

Of course you could make your own motor controller, the simplest way to do that is to put a lamp dimmer switch before the rectifier but it won't be very good because the torque would be reduced considerably below the 50% speed setting. It's possible to make a better motor controller but it certainly isn't a project for a novice.

Note that for safety reasons, the motor's metal case and that for the drill press needs to be connected to the earth/ground safety conductor on the mains supply.

How do you know it's 130VDC, is that the standard voltage for all treadmill motors?

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I winged it.

Most of the permanent magnet DC motors I have worked with have been 130 VDC at full speed. However, I am not sure what is going on across the pond where you are Hero, so I winged it.

This is the part that concerns me:

I was given a brand new
PM DC motor 2.80 HP @ 2089 watts 1.75 HP Cont Duty 1305 watts.

Click to expand...

Continous duty of 1305 Watts. Looking at over 10 Amps on my side of the pond and over 5 Amps on your side of the pond. Sometimes things are easied when people include their location so we all have a clue what their mains voltage is.

Thinking about it I also may have blown it as for some reason 90 Volts comes to mind now for max speed. Anyway that is why I asked for the data on the motor's name plate in detail. Most of what I have worked with are small fractional horsepower Bodine Electric Company motors. Not being at work I can't look at a few larger motors first hand.

Ron

Reloadron said:

I winged it.

Most of the permanent magnet DC motors I have worked with have been 130 VDC at full speed. However, I am not sure what is going on across the pond where you are Hero, so I winged it.

This is the part that concerns me:



Continous duty of 1305 Watts. Looking at over 10 Amps on my side of the pond and over 5 Amps on your side of the pond. Sometimes things are easied when people include their location so we all have a clue what their mains voltage is.

Thinking about it I also may have blown it as for some reason 90 Volts comes to mind now for max speed. Anyway that is why I asked for the data on the motor's name plate in detail. Most of what I have worked with are small fractional horsepower Bodine Electric Company motors. Not being at work I can't look at a few larger motors first hand.

Ron

Click to expand...

Ron I believe these motors run open at 90 volts dc. They will run up to 130 volts on 220. The boards are not designed for 220, without some
modifications. I copied the info for the motor right off the nameplate. That is all there is. can anyone steer me to a surplus variable speed
controller? Many thanks Snitz. Ill. USA

Pick up a surplus 1.2 KVA Variac on eBay for cheap and use a bridge rectifier on the variable output. Its makes a solid speed controller with a smooth linear speed control rate that wont limit your torque until you blow a fuse or smoke the motor.

As far as treadmill motors go they come in all voltages. I have a number of old treadmill motors that have ratings from 90 VDC to 180 VDC. They are all rated for 1.5 HP or more at full speed and ran off of 120 VAC power sources.

Running a 90 volt motor on rectified 120 VAC usually wont bother them one bit. All you do is get more RPM's and power out of them. As long as the amps stay under their limit and it doesn't fly apart they dont mind higher or lower voltages.

I vote with tcmtech as to simple, quick and will work fine.

Ron

tcmtech said:

Pick up a surplus 1.2 KVA Variac on eBay for cheap and use a bridge rectifier on the variable output. Its makes a solid speed controller with a smooth linear speed control rate that wont limit your torque until you blow a fuse or smoke the motor.

As far as treadmill motors go they come in all voltages. I have a number of old treadmill motors that have ratings from 90 VDC to 180 VDC. They are all rated for 1.5 HP or more at full speed and ran off of 120 VAC power sources.

Running a 90 volt motor on rectified 120 VAC usually wont bother them one bit. All you do is get more RPM's and power out of them. As long as the amps stay under their limit and it doesn't fly apart they dont mind higher or lower voltages.

Click to expand...

Thanks bunches. Have already ordered the rectifiers nad am searching for a Variac.

One thing you need to look out for using treadmill motors on tools, is the RPM. Most tool motors a 1725 RPM, and treadmill motors a 2-3 or more times faster. Using just the controller to slow it down to the speed you need will cause them to over heat. When the motor is turning slower, the built in fan doesn't turn fast enough to keep the air flow going to coll the motor.