Allen Bradley starter switch problem

[calvin b]

Hey YAll,
I got a problem with me drill press starter switch... It's and old allen bradley 709 automatic starter and the damned thing chatters like hell and I have to keep punching the button to get it started.. Once it's up and running it purrs right along... I think my problem is that I'm running it off of a rotary converter.. I have 120 on two legs and 230 on the third leg.. Once it's running I get 230 on all three legs.. It does seem to help if I have my lathe idling when I go to start the DP... Any thoughts, witticisms, nasty comments ? I'm kinda stumped.. Oh here's another thing to throw in the mix.... it was 440 and worked fine at the plant when I got it.... I re-wired it to 208/230..... Motor is 3/4 hp and rpc is 2hp rated.
Calvin

 

[harrytm]

Hey YAll,
I got a problem with me drill press starter switch... It's and old allen bradley 709 automatic starter and the damned thing chatters like hell and I have to keep punching the button to get it started.. Once it's up and running it purrs right along... I think my problem is that I'm running it off of a rotary converter.. I have 120 on two legs and 230 on the third leg.. Once it's running I get 230 on all three legs.. It does seem to help if I have my lathe idling when I go to start the DP... Any thoughts, witticisms, nasty comments ? I'm kinda stumped.. Oh here's another thing to throw in the mix.... it was 440 and worked fine at the plant when I got it.... I re-wired it to 208/230..... Motor is 3/4 hp and rpc is 2hp rated.
Calvin

You need the proper starters

 

[calvin b]

Harrytm,
I'm ignorant of what I need.. The heaters are of the proper amp rating.. When you say 'starters' what do you mean.. BTW the dp came out of the york int plant in york...
Stay safe
calvin

 

[harrytm]

Sorry,....I meant to say "heaters"...and I only know enough to be dangerous but IIRC the heaters in the box need to be matched to the specific use to work correctly.

 

[calvin b]

Harrytm,
The heaters in it now are for 2.3 amps which is the max amp rating on the motor for 208/230 operation.. It's like it was originally wired for 208/230 and they just re-wired the motor for 440 operation with out changing out the heaters.. Maybe I should just give southland a call and ask them what they think.. They have helped me out before..
Thanks
Calvin

 

[Modelman]

You mean the starter contacts are chattering? What voltage is the starter coil (the coil that energizes to pull the contacts in). If It's a 240V coil, and you have it wired across the manufactured phase of the RPC, then it may not be enough load to get the voltage to stabilize, and the low voltage is the reason the contacts chatter. Once the motor comes up to speed the voltage stabilizes, and the coil stays in. That also seems to explain why it works better when the lathe motor is running.

The solution is to make sure that the coil is wired to the same two lines that come from the power company, NOT the line manufactured by the RPC. This is, of course, if the coil is 240V. Check, it should be marked on the coil itself.

Dennis

 

[Jraef]

You mean the starter contacts are chattering? What voltage is the starter coil (the coil that energizes to pull the contacts in). If It's a 240V coil, and you have it wired across the manufactured phase of the RPC, then it may not be enough load to get the voltage to stabilize, and the low voltage is the reason the contacts chatter. Once the motor comes up to speed the voltage stabilizes, and the coil stays in. That also seems to explain why it works better when the lathe motor is running.

The solution is to make sure that the coil is wired to the same two lines that come from the power company, NOT the line manufactured by the RPC. This is, of course, if the coil is 240V. Check, it should be marked on the coil itself.

Dennis

I agree with this fully, other than the fact that if it used to be 480V, it most likely used a 120V coil powered off of a control transformer, and if one side of the primary of the control transformer is fed from the manufactured leg, same problem.

If it used to be 480V and it had a 480V coil, and you didn't change that, I'm surprised it has worked at all!

By the way, fix it before you use it again. If the coil is chattering, you are burning up those contacts and on the 709, those contacts are hard to come by any longer (out of production for 30 years now)

 

[calvin b]

Hey Guy's,
Many thanks for the replies... I can't find any numbers or rating on what I think the coil is. ( yeah, I that ignorant ) But I did take some pics... It is wired as the wiring digram says.. and by not finding any numbers on what I believe the coil to be leaves me to suspect it's been replaced..
Stay safe
Calvin

 

[Doug S.]

The diagram shows your coil between L1 and L2, make sure the wires hooked to L1 and L2 are your "house power" and not the manufactured phase. Making the manufactured phase "L3" (The third phase) ALL THE TIME would seem like a logical way to make life simpler in many respects.


Regards, and good luck,

Doug S.

 

[JST]

If the coil was wired the same when you got it, and it was 440, then it is still 440 and is barely pulling in.

The chatter may be due to the very weak pull-in dropping out as the start surge pulls the mains down a bit. More-so if it is on the manufactured phase.

Newer coils may be two-voltage, lots of Cutler-Hammer high power starters are, but that one probably is single-voltage. Chances of getting a replacement are probably slim. You might have to wire a boost transformer to get it to be acceptable.

A 440 control circuit isn't what I would do, but since it is all inside, it might be OK.

When weakly pulled-in, the current ratings are not valid, by the way. And, if the coil doesn't pull in all the way, it may buzz a lot, and draw too much power, eventually burning out. So it is best to get the pull-in to be right.

You might watch it, and see if it seems weak and slow, and if it appears to be pulling in all the way.

 

[calvin b]

Hey Guys,
THANKS ! I have good news ! Took the old meter out and checked out the voltages... Sure enuff I had t1 and t3 switched ! Thanks DougS as the light bulb went off in my pea sized brain after reading your post! She started up with no problem or chatter or humming. Smooth as one could ask for but she ran backwards.. So I just switched T1 and T2.... Perfection ! I'm in your debt gentlemen !
Stay safe
Calvin

 

[Jraef]

You are still at risk for a fire on that coil! If, as it appears, it is a 480V coil and you are applying 240V, manufactured leg or not, it will eventually overheat and since there is no fuse protecting it, it will likely catch on fire. Please look into a proper 240V coil for that starter.

 

[JST]

He could boost to get the proper voltage..... likely to be more do-able than finding a 240V coil....... for a long-obsolete starter.

 

[Modelman]

You know, he really doesn't know what he has here, and neither, for that matter, do we. Apparently the motor was reconnected for 440V, but the heaters in the starter were never changed, so who is to say the coil was? Who knows, it may have worked just fine on 440V, and no one was the wiser.

First, it might be nice to find the coil to actually check if it's marked. I'm not really familiar with these particular starters, but it must be under the push buttons, because the control station (push button switch) is likely an optional add-on to a basic magnetic starter…. I just looked, I have one of these old AB 709 starters in a pile of "junk for parts" on the plant maintenance shelves, and indeed, the coil is a square fabric insulated and dipped affair encircled by a steel lamination right between the two (!) heaters. Mine has a green label affixed that gives the ratings; 220V 60Cy, 208V 50Cy, 110V 25Cy. YIKES! It's so old it predates the adoption of Hz as the unit of measure for frequency.

It really wouldn't be a bad idea to, after first locking out the power, pull the push button, pull the coil, and inspect the condition of the main contacts, sanding the snots off if the chattering has buggered them up. If the contacts are completely burned away, then just toss it and buy a modern replacement, but they shouldn't be, a 3/4 HP motor is on the low end of the range for a Size 0 starter.

Even if the label has fallen off, all is not lost. Reassemble, restore power, and let the machine run for an hour or so, keeping an eye on the starter for smoke and other signs of distress. If, after an hour of running (the motor can just be idling, the starter coil doesn't really care) if the starter case doesn't feel abnormally hot, I'd just assume the coil was never changed, is still the original 208V/220V coil, and you're good to go.

[FONT=&quot]Dennis[/FONT]

 

[calvin b]

Modelman,
Well... According to the other diagram in the box... there are two different wiring schemes for the switch.. One for 440/480 and one for 208/230... According to that digram the switch is set up for 208/230. The heaters are n17's and are rated for 2.65 amps or something in that range.. It no longer chatters when starting and does not hum or make any other odd noises.. I ran it hard today for about 4 hours drilling half inch holes in 3/8 and 1/2 in plate. I took my handy little IR thermometer and checked the temp of the coil.. It was 5 degrees hotter than the temp in the shop.. Sorry folks but if it's gonna catch fire it's gotta do better than that.... Contacts were cleaned and appear to be in good shape. Personally I think I'm in good shape. Thanks one and all for the concern...
Stay safe
Calvin

 

[JST]

Well, Cal, someone is witholding information here, it seems........

You posted a schematic that shows it wired right across from L1 to L2. And you said it was still wired that way.

That means it is getting whatever that is, presumably it WAS 480, and now IS 240........ Dunno why you NOW say there is a different way of wiring it, unless either what you say NOW or what you said THEN was wrong..........

The fact that the coil is so cool now suggests to me that it still is a 480 coil but that its range is enough that it pulls in on 240V...... They usually get a bit hotter than "5 degrees hotter than the temp in the shop.."

if it works, that's fine.....

An AC solenoid has to pull in, or it draws too much current (check the "pull-in" vs "sealed" VA rating). If the solenoid plunger bottoms out (seals), you are good to go, it can't do better than that.

 

[calvin b]

JST,
Well in my haste and my ignorance I forgot to take a picture and post the digram that is in the box... After taking a good look at that it seems the switch can be wired either as a 480 switch or as 208/230 as it is now.(no mention of changing the starter coil ) I believe the number was something like a&b 709 bulliten 149 or some such.. There is a jumper wire that needs to be moved and I believe the inputs are different.. I only posted the
the 208/230 wiring diagram as that is all I'm interested in.. It's locking up tight and running cool... I only changed the inputs to the switch rather than rewiring the switch itself if that makes any sense. I think I'm good to go but I will keep an eye on it.. it is, after all a 1933 drill press that sees pretty regular use.. and the shop fire extinguisher
is just behind me at the exit door...
Thanks again
Calvin