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72 Powermatic 1150A drill press wiring issue

J

JBurt

Member
Joined
May 15, 2013
Messages
7
Hi All,

I got an old 72 Powermatic Drill press about a year ago and man is it awesome!

It came with a magnetic starter on it, which I don't know much about them, but it worked so I didn't worry about it. Until yesterday.

I plugged it in and I heard a crackling and I immediately unplugged it, but smelled burned electrical stuff. I took the cover off the mag starter and there is a transformer in there, which smelled more burned than anything else. I'm fairly mechanically inclined, but not electrically. Here's a picture.

<a data-flickr-embed="true" href="https://www.flickr.com/photos/155272546@N08/50089412972/in/dateposted-public/" title="image000000"><img src="https://live.staticflickr.com/65535/50089412972_c88343f61f_c.jpg" width="800" height="450" alt="image000000"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>

I don't have an idea on how to get a replacement transformer (or even why the transformer is needed, unless the switch needed a lower voltage), but I found some same brand same model old stock replacements on eBay for about $50.

Another question is do I need the mag starter switch? The DP has a 3/4 Baldor motor, here's a picture of the info plate

<a data-flickr-embed="true" href="https://www.flickr.com/photos/155272546@N08/50089414242/in/dateposted-public/" title="image000001"><img src="https://live.staticflickr.com/65535/50089414242_99374c8529_c.jpg" width="800" height="450" alt="image000001"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>

Could I just wire it straight to a switch? It's currently set up for 110v.

Would it be worth it to keep the mag starter? Other than turning the machine off if the breaker blows, what are the advantages?

Thanks everyone.
 
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W

Whitworth

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Joined
Dec 26, 2011
Messages
2,088
Best place for questions is owwm.org everything electrical forum.

But I'd agree just bypass and install a simple toggle switch.
 
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M

My Old Tools

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Joined
Jun 4, 2014
Messages
5,437
Location
Hamrick Lake, TX
The transformer provides the power to close the relay, hence "low voltage magnetic".
The advantage to a mag starter is that if you kick a breaker, it won't restart on its own when the breaker is reset. It also provides overload protection. It's required in many industrial settings. Most standard switches aren't rated as motor starters and will arc and eventually burn up when used on a motor. If you are wired 230v, you'll need to switch both hot lines.

Did you determine that the transformer is really dead? You may just need to clean the contacts in the mag starter. Dirty contacts will make them chatter and arc.
 
Last edited:
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J

JBurt

Member
Joined
May 15, 2013
Messages
7
Thanks for all the info everyone! I really appreciate it. For the short time I am just going to install a simple toggle switch (rated appropriately), but I do like the small benefits of the mag starter. I think it probably had one since at some point it was in a high school shop.

My_Old_Tools, I haven't verified anything is bad. I did check resistance across each coil in the transformer. One coil was 20 ohms, and the other was .4 ohms, which I think indicates a short, but I'm not really familiar with transformers, and I can't find a data sheet for a Hevi-Duty Electric W050 EE transformer. I guess I've got more homework.
 
M

My Old Tools

Well-known member
Joined
Jun 4, 2014
Messages
5,437
Location
Hamrick Lake, TX
That transformer most likely puts out 24v DC. It energizes when the switch closes and then pulls the contacts closed to start the motor. See if it outputs 24v when you push the button. It it does its still good. If the contacts close but chatter, they need cleaning, sandpaper or an emery board. If the transformer is shot, there are many on ebay cheap.
 
M

Maui

Well-known member
Joined
Sep 16, 2012
Messages
2,867
Location
Upstate NY
JBurt said:
Hi All,

I got an old 72 Powermatic Drill press about a year ago and man is it awesome!

It came with a magnetic starter on it, which I don't know much about them, but it worked so I didn't worry about it. Until yesterday.

I plugged it in and I heard a crackling and I immediately unplugged it, but smelled burned electrical stuff. I took the cover off the mag starter and there is a transformer in there, which smelled more burned than anything else. I'm fairly mechanically inclined, but not electrically. Here's a picture.

<a data-flickr-embed="true" href="https://www.flickr.com/photos/155272546@N08/50089412972/in/dateposted-public/" title="image000000"><img src="https://live.staticflickr.com/65535/50089412972_c88343f61f_c.jpg" width="800" height="450" alt="image000000"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>

I don't have an idea on how to get a replacement transformer (or even why the transformer is needed, unless the switch needed a lower voltage), but I found some same brand same model old stock replacements on eBay for about $50.

Another question is do I need the mag starter switch? The DP has a 3/4 Baldor motor, here's a picture of the info plate

<a data-flickr-embed="true" href="https://www.flickr.com/photos/155272546@N08/50089414242/in/dateposted-public/" title="image000001"><img src="https://live.staticflickr.com/65535/50089414242_99374c8529_c.jpg" width="800" height="450" alt="image000001"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>

Could I just wire it straight to a switch? It's currently set up for 110v.

Would it be worth it to keep the mag starter? Other than turning the machine off if the breaker blows, what are the advantages?

Thanks everyone.
Click to expand...

Yes, you can wire it directly to an appropriately rated single phase 110V switch. You can buy the various components you will need at Home Depot for about $10 or less. It is a very easy thing to do if you are familiar with how to wire up an on/off switch. I have literally done dozens of them.

Maui
 
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