Can my machine work without its 'reset'

[flynnboy]

My milling machine has a broken 'reset' button/circuit breaker.

Can the machine work properly without its circuit breaker/reset button ? If so can I simply remove it?

Thanks for any advice

[steam4ian]

G'day Tel

Maybe you can enlighten us as to what the Reset button does on your mill. Then we can put the lad out of his misery.

Regards,
Ian

[baggo]

Hi Flynnboy,

If you download this manual from Grizzly the circuit diagram looks very similar to yours:

www.grizzly.com/images/manuals/g1005z_m.pdf

This also shows 6 wires from the motor but it is a dual voltage. Yours may only be a 220volt motor so does not need the extra leads. The earth lead should connect to the motor chassis, possibly by one of the connection box mounting screws or a separate screw inside the box. I don't think it should be connected to the terminal block although I could be wrong. If the earth wire has broken off you should be able to see where it was originally connected.

You could run the motor without the trip/reset if you just short the two terminals (connected to the trip) together but you will have no overload protection for the motor other than the fuse in the mains plug. Shouldn't be a problem in the short term so long as you don't take ridiculous cuts and stall the motor!

John

[wayne]

The wiring diagram for a grizzle ie 1hp with internal circuit breaker, in the UK the circuit breaker would be refer to as an overload, also note the diagram dose not show a 13 amp fused plug.
Overloads are designed to protect the motor from burning out during overload and are normally rated (set on adjustable versions) at + 10% of the current the motor pulls. On some small motors they are mounted in the terminal box on the motor as in this case, or mounted as part of a contactor arrangement in the starter box. All motors above 0.37kw must have overload protection in addition to short-circuit protection (fuse, mcb, mccb rcbo ect), this rule has been in for a long time now.

RS sell the push button type mounted in terminal boxes in different ratings, better still get one from the distributor of your unit.

In short overloads protect your windings in the motor from over heating, if you put excessive load or stall the motor.

If the overload is faulty change it do not link it out as a fix/permanent measure (actual current must be verified with a amp meter). If the overloads ok i.e. high amperage (current must be checked with a amp meter) find the cause as to why its tripping.

I would also do some checks on the motor firs and definantly prior to purchasing any parts

Note Repeatedly resetting a motor overload over a short period permanently damages the insulation of the motor windings and will shorten the life of the motor.

[flynnboy]

Hi Guys

Great stuff. I have just heard back from Axminster and they say I can simply join the two wires from the circuit breaker together. I had better just explain. The breaker was smashed to bits and all I have left are the two wires from the breaker which are still connected to two terminals, so, they say just join them together - do you agree ?

The motor specs are 3/4 hp - 240 V - 4 Pole

I will be getting a new breaker I just want to get my machine running in the short term until I receive it and I can guarantee it will not be overloaded in any way.

baggo, you are right about the earth, I took the battered connection box off to replace and in so doing found the remains of the broken connection to the chassis.

Thanks again guys for your input

[flynnboy]

Hi again Guys

It looks like I have more problems than I thought.


I'm afraid that my worst fears are perhaps being realised because I was never certain if there was more damage than the obvious done to my machine. I have done what has been suggested with the circuit breaker wires and when I switch on absolutely nothing happens. I can think of only one other possibility.

I also lost the micro switch from the pulley housing cover, this I guess was a safety device so that the motor was tripped off every time the cover was opened. The micro switch was connected to the switch gear by simply 2 wires a brown and a blue. I have simply sheathed these two wires with insulation for safety - could this be the reason nothing is happening when I switch on ? If so what can I do without buying a new micro switch ?

[baggo]

No, the motor will not run without the safety switch (microswitch) on the belt cover operated. It's there to stop you running the machine with the belt cover open of course. It will run with the two wires connected together but again, the safety aspect has gone. It's up to you but will get the machine running until you get a new one. Some machines have a safety switch on the chuck guard as well for the same reason.

John

[flynnboy]

Hi John,

Thanks for that. It runs against the grain of lifelong learning to connect a live and neutral wire together Can you please just reaffirm this will do the job ? I appreciate the safety aspect but I just need to get it running in the short term until I get my replacement bits - I just want to reassure myself it is still working after its bad tumble to the road

Thanks again

[flynnboy]

YEEEEHAAAAA

Hey it's working guys ;D

Thank you ever so much all of you ! All I need to do now is order my replacement bits.

Blxxxxy fantastic ! It's been out of commission for 4 months and I never really knew if it was going to work again.

Marvelous !

[Tel]

The 'button box' on my RF30 wasn't working when I got it either - I just replaced it with a simple toggle switch that works fine. No lock out micro on the belt guard of the ol' girl - I think she pre-dates them, but in point of fact I had to remove the belt guard any'ow, owing to lack of headroom in my under the house workshop. It was either that or cut a big 'ole in the living room floor.

[steam4ian]

G'day Tel et al.

Reading between the lines of my learned friends it now becomes apparent that the reset button (switch) is in fact the motor's thermal protective device, it is the overload switch.
Running without it compromises the motor.

I recommend you replace the toggle switch with the appropriate overload. Leaving it out may well void your fire insurance.

Regards,
Ian

[Tel]

Oops! My mistake - I was talking about the On/Off box on the machine itself. The thermal is OK on mine.

[ettingtonliam]

I'm setting up a Centec horozontal mill, which has a MEM no volt release stop/start switch. I've also got an emergency stop switch (big red button thingy) that I am persuaded is now a desirable/essential fitment. My question is, does the emergency stop get wired in between the supply and the MEM starter, or between the MEM starter and the machine? My thinking is that it should go between the supply and the starter, so that if the emergency stop is operated, the MEM also cuts out because of no voltage.

Regards
Richard

[baggo]

Mar 9, 2009 13:00:13 GMT ettingtonliam said:

My thinking is that it should go between the supply and the starter, so that if the emergency stop is operated, the MEM also cuts out because of no voltage.

That sounds reasonable, otherwise it may start up again when you reset the emergency stop?

John

[houstonceng]

But Baggo, if you put the Emergency Stop in the coil circuit of the MEM, it would need the Start button to be operated again to re-start the M/C if either the E-Stop or Normal Stop button were operated.

OK. If fitted in the Mains supply to the switch-gear, it would stop the m/c if the MEM ever got stuck in the "on" position. Just make sure the E-Stop is rated to break the full motor current.

[baggo]

Hi Andy,

Had a quick look at an MEM I've got lying around and it looks easy enough to put the emergency stop in series with the coil. Probably would be a better way of doing it

John

[wayne]

On Mem starters, the wiring diagrams show the emergency stop button in series with the contactor coil (Direct on line starters only). For current standards when you hit (operate) the emergency stop button for the machine it should stop and not restart until the emergency stop has been un latched reset and the start button pressed. The stop button on old mem starter is also the reset button for strters fited with thermal overloads.

Note one problem you may have is that your emergency stop button will be rated naf all ampage the reason it must be wired in whats called the control circuit, also it will be rated at 230V max, fine with a 230v control circuit. But I bet of your machine is 3 phase and the voltage of the control circuit will be 400 or 415v, try getting a 400v latching Emergency Stop switch, nobody dose them. If you whant to fit an emegancy stop to an old three phase machine read on

One of the reasons you can see old collage machines in perfectly good nick on ebay is they cannot be easily brought up to modern standards at first thought. However in most cases its easy to bring 3 phase machine up to current electrical safety standards, "fit an inverter" which uses low voltage type control circuits for remote staring and stopping, all safty latches and emergency stops must be fitted in series in the stop circuit.

The start buton will need to be of the corect type and will need to be conected to the inverter on its own, it will either have to be laching or non latchingh depending on the type of inverter. There you have it, you will have a machine which can be easily converted (with the exception of coolant [pump and Lighting these would probably need replacing with modern low voltage replacements)

Note to the above paragraph
Not all inverters use the same control circuit, check with your supplier first, tell him/her you want to fit an emergency stop to the unit, and it must not restart automatically on remaking the emergency stop. Your motor will need to be three phase 220 to 240v delta / 400 to 415 star to work off the commonly available inverters.

Please note if you have 3 phase fixed speed machine for example a grinder you can still use an inverter, just lock the speed at a set speed in the inverters software. Most inverters incorporate soft staring, so it can be easier than swapping to single phase above 1hp.

In Addition older starters normally found as part of the machine especially inside the castings used the stop button as the original emergency stop, these had no latching open facility and did not need to be reset. These machines can be converted as above but the rewiring is more involved.

Of course for three phase you could always use a can use a DOL starter with a low voltage control circuit but you would still need converter. For just one machine alone it will probably be more expensive than an inverter.

[ettingtonliam]

Wayne
Thanks for that info. The emergency stop is the one originally fitted to the machine when it had a 3 phase motor. I am using a single phase motor, and the MEM is the one which came with the single phase motor. I'm not very good with electrical matters, and if this is going to be complicated, I'll just use the MEM.

Regards
Richard

[houstonceng]

ettingtonliam

If you're "not very good with electrical matters" it may be best not to try. Electricity is too dangerous a fluid to be toyed with.

As the old notice used to say "Dieses elektrikmachine is nicht fur fingerpoken. Es easy poppencorken, blowen fusen und killenself - mit spitzundsparken"

If you were local, I'd offer to come round and assist (with the wiring, that is !). Perhaps others may be willing to do the same if you live in a remote location ?

Failing that, a model number for "the MEM" and a photo (PM if necessary) would help.

Otherwise, trying to tell you in words, how to wire it up, is like trying to explain to someone who's been blind from birth what the colour blue looks like.

[ettingtonliam]

OK, I'll just stick with the MEM. MEM starters have been good enough ever since I got my first lathe in 1965, I reckon they should see me through my last 20 years or so, God willing. After all, apart from the size of the button, whats the difference, in an emergency, between hitting the MEM 'Stop' button, and hitting the big red button? I agree the MEM could stick, but I can't remember that happening before, and anyway theres always the main isolator switch if all else fails.

Regards

Richard