Long Shot - Bench Grinder

Reply

  #1  
Old 09-06-17, 05:31 PM
D
Forum Topic Moderator
Thread Starter
Join Date: Sep 2012
Location: USA
Posts: 1,087
Received 48 Votes on 41 Posts
Long Shot - Bench Grinder

This is going to be a long shot on the 1st part but the 2nd inquiry will be pretty easy for some of you guys.

When we bought this home about a month ago, it came with a shed that has a little (shop) work area. Because the couple was older & he has now been moved to a veterans home because of dementia, they ended up leaving some items behind. Some items useful, some junk.
One item left behind was an old bench grinder. The label is faded & in not easily legible. It has a broken switch & I would at minimum, see if it works, if so, buy a switch for it. If it does work, I know I can just buy a generic toggle switch but its got four wires to it of which three are red & one is black. I checked the wires with a volt meter & when touching the black wire & the red wire in the back I get 120 v. I get nothing with any other options/connections. I tried using a jumper using all the red wires in various options & nothing.

So, first, can anyone identify this grinder?

Second, can someone tell me how I can test this by jumping the wires? There is also a green wire under the grinder that seems to be connected on both ends inside the motor & NOT connected to the switch.
http://www.doityourself.com/forum/at...1&d=1504740239

http://www.doityourself.com/forum/at...1&d=1504740275

http://www.doityourself.com/forum/at...1&d=1504740306
 
Attached Images    
Sponsored Links
  #2  
Old 09-06-17, 05:38 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,855
Received 1,203 Votes on 1,113 Posts
Bench grinders use a two pole switch. The wires just get connected straight thru the switch.
You should be able to locate the two wires that are the feed and connect them directly to the two remaining wires.
 
  #3  
Old 09-06-17, 05:45 PM
D
Forum Topic Moderator
Thread Starter
Join Date: Sep 2012
Location: USA
Posts: 1,087
Received 48 Votes on 41 Posts
Hummm, ok, but isnt one a ground? The black one? When I used a jumper to try to get it to run, I did not include the black one in any of the (jumping) options. I used all three red ones (using 2 at a time) in various options/sequences. I never used all three red, nor all 4 wires all at once / at the same time, in any jumping options.
I could only find one "hot" red wire while using the the black as a ground. Otherwise, I got nothing in any attempt.
 
  #4  
Old 09-06-17, 05:50 PM
D
Banned. Rule And/Or Policy Violation
Join Date: Sep 2017
Location: USA
Posts: 516
Received 0 Votes on 0 Posts
The green wire should be the ground.
 
  #5  
Old 09-06-17, 06:02 PM
D
Forum Topic Moderator
Thread Starter
Join Date: Sep 2012
Location: USA
Posts: 1,087
Received 48 Votes on 41 Posts
I touched one end of my jumper wire to the black wire & quickly.... very quickly, brushed the other end of my jumper wire across the red wire that I get voltage out of, & sparks flew. So, that aint workin'.
With the jumper still on the black wire, I touched another red & nothing. I touched the 3rd red wire & nothing.

So, while the green maybe a ground within the case of the grinder, I'm still thinking the black is my ground in the switch.

Now what???
 
  #6  
Old 09-06-17, 06:25 PM
D
Banned. Rule And/Or Policy Violation
Join Date: Sep 2017
Location: USA
Posts: 516
Received 0 Votes on 0 Posts
I never saw black as a ground on AC current.
 
  #7  
Old 09-06-17, 06:36 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,855
Received 1,203 Votes on 1,113 Posts
I don't see green on the switch. If it is..... you need to open the motor base and find the incoming power cord which should have at least a white and black wire and possibly a green. Someone may just have spliced on random colored pieces of wire.
 
Attached Images  
  #8  
Old 09-06-17, 06:49 PM
D
Forum Topic Moderator
Thread Starter
Join Date: Sep 2012
Location: USA
Posts: 1,087
Received 48 Votes on 41 Posts
The green wire discussed doesnt go to the switch. It is kinda "looped" coming out of, then back into the bottom of the housing. I tugged on it to see if it was loose & it appears to be connected at both ends in there. I dont think the green wire plays any part in this but I mentioned that it was hanging out of the bottom of teh housing just for reference in case it was related... but, again, I dont think it is related to the issue here.
There are only 3 red wires & 1 black wire connected to the switch. in YOUR blown up picture, you have a line drawn from the black wire to a red wire. The black wire is what I assumed & used as the ground when checking voltage with a meter. The red wire you have connected by the yellow line to the black wire is the one that is showing 120 v.
I get nothing from the other two red wires.

When I jumped the black & red wire that you have connected with the yellow line, I get sparks.
 
  #9  
Old 09-06-17, 06:52 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,855
Received 1,203 Votes on 1,113 Posts
You will get sparks when connecting them.
You're connecting an almost dead short (motor) to the AC line.

I was looking at another typical grinder switch and connects in the opposite direction.

If you find the two line wires..... the ones that measure 120v.... the other two are the motor.
 
Attached Images  
  #10  
Old 09-06-17, 08:06 PM
D
Forum Topic Moderator
Thread Starter
Join Date: Sep 2012
Location: USA
Posts: 1,087
Received 48 Votes on 41 Posts
So I need to connect/test them (in general) the way you have them in your 2nd pic? Black to red... then the other two reds together? Is that generally speaking how they are supposed to work?
 
  #11  
Old 09-06-17, 08:14 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,855
Received 1,203 Votes on 1,113 Posts
The switches can work either way. The first picture was the way my grinder was set up. One of my two poles went bad so I bypassed it and am using the switch as a single pole.
 
  #12  
Old 09-06-17, 08:31 PM
D
Forum Topic Moderator
Thread Starter
Join Date: Sep 2012
Location: USA
Posts: 1,087
Received 48 Votes on 41 Posts
OK great. Thanks PJ. I'll try that tomorrow when I get home & will report back. Thanks again!
 
  #13  
Old 09-07-17, 02:18 PM
D
Forum Topic Moderator
Thread Starter
Join Date: Sep 2012
Location: USA
Posts: 1,087
Received 48 Votes on 41 Posts
PJMax, you are correct in post 9. That worked & the grinder does work. Thanks for your input.

Now, would anyone happen to have any inclination on the make of the grinder & possibly the model number? It looks like the model # is 306C, but I aint sure. I did Google it but didn't get any specific matches. I did see someone had a similar one for sale in south Africa a few years ago.

If we cant get a make & model, will just any similar 4 wire switch work? I'll just try to find one close.
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description: