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Mekanizm
01-07-2010, 01:54 PM
Or more specifically, do I need to change anything in this control box?

This is a Taiwan origin lathe that was running on 440v. I am now rewiring the motor to 220v with a static phase converter. The manual only says to rewire the motor to change voltage.

I do believe that I need to change an input lead on the control transformer from 440 to 220, Correct? I believe the two small fuses are on the 120v output of the transformer so they are OK?

The three big fuses at 30A are still OK I assume?

Does this thing appear to have some type of solid state type heaters that needs to be exchanged or adjusted?

I just don't want to learn anything here the hard way!

http://i255.photobucket.com/albums/hh152/topafranklin/DashinPrince.jpg

http://i255.photobucket.com/albums/hh152/topafranklin/Transformer.jpg

Doozer
01-07-2010, 02:24 PM
Those things with the red dial and the yellow buttons are overloads.
Adjust the red dial for current draw, yellow button is the reset.
There also may be a lever for auto or manual reset.

--Doozer

Bruce Griffing
01-07-2010, 02:26 PM
The fuses may not be OK, depending on the requirements of the motor. For sure, at half the voltage, the motor will draw twice the current. What is the HP rating of the motor?

Mekanizm
01-07-2010, 02:44 PM
9 amp at 220 volts.
http://i255.photobucket.com/albums/hh152/topafranklin/MotorDataPlate.jpg

Bruce Griffing
01-07-2010, 03:03 PM
Your motor is rated a 9 amps per phase at 220v. The existing fuses should be OK unless there are other loads on them.

Mekanizm
01-07-2010, 03:51 PM
Great, thanks

About the overload relays.....

One is set to 12 amps and the other is set to .55 amps. There is a fractional hp coolant pump on this lathe in addition to the 3 hp main motor.

The manual indicates that the lathe may have been shipped default wired for 220. When I obtained the lathe, it was operating on 440 volts. So is there only one adjustable overload relay for all three legs of the 3 hp motor and it should be set to something above 9 amps? Maybe in this case, it was never readjusted lower for the 440 volts corresponding amps.

Maybe in this case I leave them alone????
http://i255.photobucket.com/albums/hh152/topafranklin/overloadrelay_2.jpg

http://i255.photobucket.com/albums/hh152/topafranklin/OverloadRelay_1.jpg

Mekanizm
01-07-2010, 03:54 PM
Am i right in thinking also that I remove "S" lead fron the transformer tap marked "H4" and relocate it to tap marked "H2"?

Doozer
01-07-2010, 05:26 PM
Some may disagree with me on this, but if you turn up the overloads and they still kick out, I would remove them. I view overloads like these as being for motors that run un-attended. Like vent fans and compressors and pumps running when people are not around. The lathe is only on when you are running it, so no problem. If something catastrophic happens, like a dead short in the windings, the fuses or the breaker will still kill the power. If you loose a phase, the motor starts to growl, and you shut it off. I vote to remove the overloads. Some may not agree, but I believe it is safe in this application.
If they were name brand overloads like Telemechanique, Square D, or Allen Bradley I would say to see of you could buy the right ones, but they look like China brand stuff, and it is doubtful that different ones would directly mate up to your contactors.


--Doozer

Black_Moons
01-07-2010, 05:44 PM
doozer: I believe the overload on a lathe would be to prevent overheating the motor from extended cuts that are above the faceplate current rating (ie draw more HP then the motors rating)
ie, actualy overloading the motor slightly in use for extended periods, Not outright faults (that would often trip a breaker anyway)

Also OP never asked about removing the overloads or mentioned them triping, AFAIK he hasent even applyed power yet (And should'nt untill he has everything rewired properly for certain)

Doozer
01-07-2010, 06:20 PM
Black Moons-

Good point about working the motor beyond its service factor.

I see you did not capitalize my name.
Are you intending to show disrespect to me?

--Doozer

wmgeorge
01-07-2010, 06:33 PM
I'd change the tap on the transformer primary to the setting for 220 volts, I can't scroll back right now but I think it was H1 and H2, turn the heater adjustment on the main motor down from 12 to say 10 and see what happens.

My guess is they changed the transformer tap and nothing else when it was switched over to 440 volts. Since this is 3 phase, you know about switching any two phase leads to reverse if needed.

The fuses were the wrong rating for 440 volts, but oh well.
Good Luck!

Now I see you are running on a static converter, best thing you do is try to make it into a rotary converter by hooking another 3 phase motor to it. Lots of details on here, search would bring them up.

whitis
01-07-2010, 08:40 PM
I do believe that I need to change an input lead on the control transformer from 440 to 220, Correct? I believe the two small fuses are on the 120v output of the transformer so they are OK?

The three big fuses at 30A are still OK I assume?

Leave the small fuses alone. As for the big ones, in theory they should be doubled when lowering the voltage but it appears the ones already installed are probably too big. I doubt that wiring could handle 60A and that would be an awfully big motor. So leave them alone.

Changing the input lead on the transformer sounds good.



Does this thing appear to have some type of solid state type heaters that needs to be exchanged or adjusted?

Solid state type heaters? What in are you talking about? Why do you think you should have something like that in lathe? Are you thinking of a solid state overload relay (not a heater)?

There are six cables coming into the top of the box. Why don't you tell us, left to right (#1 to #6), what they connect to? I suspect the one on the left is power in and the two on the right go to two different three phase motors, both of which will need to be rewired for 220V. #5 appears to have an extra pair of wires. Fan? Some sort of sensor?

Number the relays left to right #1 to #5.
There are some odd looking devices above two of the relays (#3 and #5) which appear to be in series with the motor outputs. Some sort of current sensing/overload protection that removes power to the control relays? If so, it may need adjustment. Looks like there is an adjustment screw.
These only connect to two legs of three phase power. Probably good to
make that your real legs. Investigate whether these devices will be affected by 220V vs 440V as well. These may be integrating thermal overload devices, perhaps that is what you were thinking of with "solid state heaters"? Are these passive devices with a mechanical adjustment or do they need logic power?

The device between relay #2 and the small fuses looks like a bridge rectifier, possibly to run the relay coils on DC instead of AC for reduced hum.

Figure out which of the three phase inputs connects to your control transformer and put those across the real legs rather than the synthesized one. If that conflicts with the directions regarding the overload devices above, then maybe moving the control transformer to use the same legs is advisable.

I would suggest posting a closeup of relay #5 and the device above it., likewise #3. Also a couple overall views, similar to the first pic, but one taken from below
and one from the left so the wiring which is not visible in the first pic can be seen.

Relays #3 and #4 may be spindle forward/reverse, with spindle on cable #5. Relay #5 may run the auxiliary motor on cable #6. Relay #1 appears to be associated with the extra wires on cable #5. Spindle motor fan? Relay #2's purpose isn't clear. Perhaps a run/stop latch?

It would appear that the two terminals on opposite sites of the relay with the round symbol in between are probably the relay contacts and that the other 6 contacts are probably normally open contacts between the top side and bottom side in vertically aligned pairs. All the relays have the same model number and therefore the same coil voltage, so why are both the 110V and 220V output taps on the control transformer used? Is one for something external like the motor cooling fan?

If you don't have a wiring diagram for the lathe, I suggest you draw one. Since you are changing voltage and using a mickey mouse three phase source, you should probably know what you are dealing with.

Just based on what I can see:
- move the control transformer power input to 220V tap
- Rewire the spindle motor for 220V
- Rewire the accessory motor for 220V
- Adjust the overcurrent trips
- connect the real legs to R&S and the fake leg to T.

There is less chance of nasty surprises going from 440V to 220V than vice versa.

Mekanizm
01-07-2010, 11:20 PM
I am also in the middle of wiring up a doall bandsaw to also run off of this same static phase converter. More on that later. In that 440 to 220 conversion I had to deal with actual analog devices called Motor Control Heaters. Remove two screws and replace, three times.

So I move over to the lathe rewire job and it seems that in it's prior life nobody took any pains to tweak it in at 440v. I have just about figured this out now with all the input. Big help. Solid state heaters was a mechanical guy sticking his electrical foot in his mouth:o

Ok lets get right to business:D The cables coming in from the top from left to right; 1) Incoming power, 2) 110 to the motor control switches (Main and coolant), 3) Brake pedal limit switch, 4) Limit switch for spindle control, 5)power out to main 3 hp motor, and 6) Power out to coolant pump.

The relays from left to right 'appear' to be 1) Unsure, gotta look closer tomorrow. Something with the rectifier maybe and a Motor brake? 2) Spindle control lever stop?, 3 & 4) main motor on, and 5) coolant pump motor. I do have a wiring diagram (but that doesn't mean I always read it properly).

Those two odd looking devices above relays 3 and 5 are labeled 'Thermal Relay'. On the Doall it appears three devices were required to do the job done by this one guy. Advances in technology? Here it looks like one for the main motor that needs to be reset to around 10 and one for the coolant pump. All I got on him is 1/8 hp 3 ph.

The device that looks like a bridge rectifier, could that be for a motor brake? This rectifier guy looks to be fed from the 220 output on the transformer. The 110 side goes to the motor controls.

I agree that the fake leg should be "T". The transformer is fed off of "R" and "S". I just got done bugging out my supply conductors for this. I wouldn't mind getting the right fuses if that should help.


A little more information. I could use help here as well. Don't want to make a Darwin award out of this.

I have a 3 phase 5 hp motor on hand and a stand built for a future RPC. In the meantime I am using the static phase converter to run a 3hp milling machine. I am wiring the three machines to be all in parallel with each other. I am using three phase plugs and receptacles for the disconnects. I have made sure the fake leg is the same for all. Can I run any two machine simultaneously and get near full power?

Legit? I know there is insufficient info presented here to determine code compliance but is the premise OK?

Thanks for the help. It made me realize that I had not considered the coolant pump probably needs rewiring. I will explore that tomorrow.

Thanks Again

RobbieKnobbie
01-08-2010, 12:33 AM
Leave the small fuses alone. As for the big ones, in theory they should be doubled when lowering the voltage but it appears the ones already installed are probably too big. I doubt that wiring could handle 60A and that would be an awfully big motor. So leave them alone.

Changing the input lead on the transformer sounds good.


Solid state type heaters? What in are you talking about? Why do you think you should have something like that in lathe? Are you thinking of a solid state overload relay (not a heater)?

There are six cables coming into the top of the box. Why don't you tell us, left to right (#1 to #6), what they connect to? I suspect the one on the left is power in and the two on the right go to two different three phase motors, both of which will need to be rewired for 220V. #5 appears to have an extra pair of wires. Fan? Some sort of sensor?

Number the relays left to right #1 to #5.
There are some odd looking devices above two of the relays (#3 and #5) which appear to be in series with the motor outputs. Some sort of current sensing/overload protection that removes power to the control relays? If so, it may need adjustment. Looks like there is an adjustment screw.
These only connect to two legs of three phase power. Probably good to
make that your real legs. Investigate whether these devices will be affected by 220V vs 440V as well. These may be integrating thermal overload devices, perhaps that is what you were thinking of with "solid state heaters"? Are these passive devices with a mechanical adjustment or do they need logic power?

The device between relay #2 and the small fuses looks like a bridge rectifier, possibly to run the relay coils on DC instead of AC for reduced hum.

Figure out which of the three phase inputs connects to your control transformer and put those across the real legs rather than the synthesized one. If that conflicts with the directions regarding the overload devices above, then maybe moving the control transformer to use the same legs is advisable.

I would suggest posting a closeup of relay #5 and the device above it., likewise #3. Also a couple overall views, similar to the first pic, but one taken from below
and one from the left so the wiring which is not visible in the first pic can be seen.

Relays #3 and #4 may be spindle forward/reverse, with spindle on cable #5. Relay #5 may run the auxiliary motor on cable #6. Relay #1 appears to be associated with the extra wires on cable #5. Spindle motor fan? Relay #2's purpose isn't clear. Perhaps a run/stop latch?

It would appear that the two terminals on opposite sites of the relay with the round symbol in between are probably the relay contacts and that the other 6 contacts are probably normally open contacts between the top side and bottom side in vertically aligned pairs. All the relays have the same model number and therefore the same coil voltage, so why are both the 110V and 220V output taps on the control transformer used? Is one for something external like the motor cooling fan?

If you don't have a wiring diagram for the lathe, I suggest you draw one. Since you are changing voltage and using a mickey mouse three phase source, you should probably know what you are dealing with.

Just based on what I can see:
- move the control transformer power input to 220V tap
- Rewire the spindle motor for 220V
- Rewire the accessory motor for 220V
- Adjust the overcurrent trips
- connect the real legs to R&S and the fake leg to T.

There is less chance of nasty surprises going from 440V to 220V than vice versa.

GREAT POST! I've never laughed so hard as when I read your fifty page rambling diatribes!

I thought the post where you told the guy who had just bought his first mill drill that he'd need to put the 'toy' for his wife through a vibratory finisher and passivation and electroplating and the split collets on an on and on... that was going to be your best work, but now that I've read it through again, this one is even funnier!

Keep 'em coming!

Richard-TX
01-08-2010, 02:38 AM
I am now rewiring the motor to 220v with a static phase converter.

My advice? Don't. Go any other route but don't do a static.

Peter N
01-08-2010, 03:54 AM
My advice? Don't. Go any other route but don't do a static.

Why?
I run a Bridgy, Colchester Lathe, and a J&S surface grinder all from one static phase convertor. All have 2hp main motors and the lathe and grinder have auxilliary fractional hp motors. No problem.

Peter

Mekanizm
01-08-2010, 09:38 AM
GREAT POST! I've never laughed so hard as when I read your fifty page rambling diatribes!

I am glad your laughing:D.

I'm not.

I feel like I am one small step away from being a component in a Vandergraff Generator and whitis came across to me like a Professor to a Student and I appreciate his time and expertise greatly. This was precisely what I was looking for.

He took my incomplete information, filled in the blanks so I could follow his logic and summarized with five point to address.

Until told otherwise (with their supporting logic), these five points have summed it up concisely and I am acting on them.

wmgeorge
01-08-2010, 11:07 AM
When I made my reply BTW, I was assuming you were going to rewire the motors for 220 volts. That and changing the settings on the motor OL heater solid state devices, and the transformer tap is all you need to do. Been there, done that many times.
The fuses were never changed over for 440 volt operation, so leave then as is...

Mekanizm
01-08-2010, 01:33 PM
When I made my reply BTW, I was assuming you were going to rewire the motors for 220 volts. That and changing the settings on the motor OL heater solid state devices, and the transformer tap is all you need to do. Been there, done that many times.
The fuses were never changed over for 440 volt operation, so leave then as is...

You got it right on wmgeorge. I am starting to feel a lot more comfortable about this. Thanks.

Upstream of all this is 10 ga wire and a 30 amp breaker previously installed.

wmgeorge
01-08-2010, 02:53 PM
And I don't know how big a static converter ( 3 or 5 Hp?) you have HP wise, but I had made my own. Did not like the way the lathe (EMCO) worked.

So I got a like new 5 HP 3 phase motor (cheap odd ball mount) and put it on the converter directly unloaded of course. Unloaded it acts as a rotary phase generator and draws little amperes. Then took my 3 phase feed for the lathe directly off the T leads all three from the rotary converter (now) and feed my new lathe. I added some old motor run capacitors that I had, to the generated lead to balance out the feed to the lathe, under power. It works like a charm.

Both speeds on the lathe motor work and I have full reverse operation on both speeds.

Why did I go this route other than a VFD? I had the stuff and what I needed to purchase I got cheap.

Mekanizm
01-08-2010, 05:20 PM
After making all the changes and carefully reviewing them, the lathe started and ran perfectly.

I appreciate everybodies input. I didn't want to tackle this all by myself.

Thanks Again!

The next project will be to get the RPC up and running.

whitis
01-10-2010, 02:44 PM
GREAT POST! I've never laughed so hard as when I read your fifty page rambling diatribes!

I thought the post where you told the guy who had just bought his first mill drill that he'd need to put the 'toy' for his wife through a vibratory finisher and passivation and electroplating and the split collets on an on and on... that was going to be your best work, but now that I've read it through again, this one is even funnier!

Keep 'em coming!

*Puzzle Look* I don't think diatribe is the word you are looking for. A diatribe is "a bitter, sharply abusive denunciation, attack, or criticism". Neither post was about criticizing or abusing the poster, just providing detailed information. As for the other thread, there are some situations where craftsmanship matters.

OP: yeah, the rectifier could be for DC injection braking. But there area couple reasons to originally suspect it wasn't. One of the terminals appears to connect to the coil contact on one relay (and probably daisy chained to others from there). And without some sort of limiting device the motor might look like a near short across the control transformer at DC which might be hard on it. Would explain what the 220V tap is for, though. And if you have a brake switch, you need something to back that up and I don't see anything that looks like a more sophisticated braking system. And when the overload on the control transformer causes a brownout on the relays causing them to drop out, that isn't incompatible with braking and most of them probably would be commanded to drop out anyway. However, if the control transformer is used for braking, it is possible this could be one of the learning things the hard way situations you were worried about. If the motor is rewired for 220V from 440V, it draws twice as much current at the same voltage. Which means you might want to move braking down to the 110V tap. The wiring diagram may have a hint as to whether this is expected by showing the appropriate wire connected to either position.

When you write "limit switch" I suspect you may be referring to a microswitch (though some aren't all that "micro") a switch that operates off small mechanical travel and often senses the position of things and which are indeed frequently used for limit switches among other applications. However, even if the brake pedal and spindle control switch are at the limits of their travel when they trip the microswitch, that doesn't make it a limit switch. A limit switch is one which is usually activated when a controlled mechanism reaches the limit of motion and usually interrupts power so the mechanism isn't driven past the limit.

Thermal (overload) relay sounds right. This is a device that is somewhat similar to a circuit breaker except it is designed to protect the motor rather than the wiring and would probably be matched to the characteristics of the motor (or an industry standard model) and may not directly interrupt power but send a signal to another relay to do so. This eliminates the need for another set of high current contacts and allows other actions to be taken such as shutting down the spindle if the coolant pump overloads. If they didn't replace the main fuses with something smaller when they changed to 440V, there is a good chance they left the settings on these at the original settings appropriate for 220V. The current rating on the spindle motor nameplate at 220V should be an indication of where the adjustment should be set. If the coolant pump is only 1/8HP, then an appropriate setting might be around 0.5A. Gets a little confusing, though, when only 2 out of 3 phases go through the thermal overload relay and does, for example, 10A setting mean 10A in each phase or 10A combined?

Don Young
01-11-2010, 01:03 AM
Unless specified otherwise current in a 3 phase system is taken to be current in any/each phase. Adding currents requires consideration of phase angle. It is interesting that in a balanced system the sum of the currents in any 2 legs is equal to the current in the third leg, despite the currents in all three legs being equal. In other words, for 10 amperes in each leg, the sum of the currents in any two legs is also equal to 10 amperes. If you have a clamp-on ammeter and a balanced system, try it by measuring each leg, then 2 at a time. Since phase shift is involved you have to have the 2 legs in the same direction. Of course if you measure all three legs you get zero.

Mekanizm
01-11-2010, 09:32 AM
Whitis,
Thanks for your help both here and in the transformer thread.

I did start and run this lathe but I now realize that I have not yet activated the braking system. I will take another look at it before I try it. The manual (if we want to call it that) doesn't refer to anything other than the main motors nine lead swapout. I agree with the clarification on the "limit switch" terminology. I just ran with the asian translation and didn't think about it. I really hate to use wrong terminology and mislead.