Electrical Gurus-Help!

Lil Foot · Feb 24, 2020

The forward-off-reverse selector switch on my engine lathe died. (housing broke up)
After a lengthy search, it became obvious the same switch is no longer available, but the switch I found was supposed to be a direct replacement, even has the same number, (HZ5B-10) and was touted as being a direct replacement for import metal lathes. However, I am unsure as to how to wire it, and would appreciate any help you folks good offer. Bear with me for the long post.
1st pic shows new and old switch. (old with zip ties)
2nd pic shows a red w/cream colored jumper from the original switch wiring.
3rd & 4th are the wiring diagram & parts list from lathe manual

Motor is single phase 220V.

Lil Foot · Feb 24, 2020

The original switch checks as follows:

Old Switch

“1” position T1 connects to T2

“0” position T3 connects to T4

“2” position T5 connects to T6

next two pics show old switch as wired:

Lil Foot · Feb 24, 2020

New switch checks as follows:

New Switch

"1" position T1 connects to T2 and T5 connects to T6

"0" position no connections

"2" position T3 connects to T4 and T7 connects to T8

As you can see, there are significant differences-
eight terminals instead of six
four terminals connected in position #1 & #2 instead of two
no terminals connected in the "0" position

Maybe I have a mental block, but I just can't see the solution.
I might be able to trace the wires back to the contactors and the the motor, but I'd rather not if I don't have to- it would require re-arranging the garage & dis-assembling a divider wall behind the lathe. (or moving the lathe-shudder)
Help!

dochsml · Feb 24, 2020

Did this new switch come with a diagram? Do the wires on your lathe have labels or are they just colored?

SidecarFlip · Feb 24, 2020

I get befuddled screwing in a light bulb so I'm no help but,

I do have a pristine Atlas floor lathe completely tooled sitting in the shop that I can sell you and it has a good bi directional switch already on it. Nice machine, one owner and very well maintained. I mean completely tooled too, including taper attachment, tool post grinder, 3 sets of headstock chucks, face plates, dog plates, centers, collets and closer, toolpost milling vice, the whole nine yards and most of the stuff has never been used and in original boxes.... and it's 110 volt, single phase. I use it for trimming brass rifle cases.

Have a nice South Bend 3 foot bed bench lathe too with a collet closer and complete set of 3AT collets, chucks, faceplates, centers and quick change cam lock tool post. Has the quick change gearbox. The Atlas also has a quick change gearbox too.

Need to sell some of the machine tools I don't use much anymore.

torch · Feb 24, 2020

Looks to me like the switches have some unused terminals -- T3 and T4 on the old switch.

So, wire from T1 old to T1 new and wire from T2 old to T2 new, then wire from T5 old to T3 new and wire from T6 old to T4 new.

dochsml · Feb 24, 2020

Lil Foot said:
New switch checks as follows:

New Switch

"1" position T1 connects to T2 and T5 connects to T6

"0" position no connections

"2" position T3 connects to T4 and T7 connects to T8

As you can see, there are significant differences-
eight terminals instead of six
four terminals connected in position #1 & #2 instead of two
no terminals connected in the "0" position

Maybe I have a mental block, but I just can't see the solution.
I might be able to trace the wires back to the contactors and the the motor, but I'd rather not if I don't have to- it would require re-arranging the garage & dis-assembling a divider wall behind the lathe. (or moving the lathe-shudder)
Help!

I must have missed this explanation before I sent my other post. It doesn’t look like that switch will work. You definitely need connections in the 0 position. I’m sure it could be rigged to work, but it would defeat the safety of making sure the switch was in the 0 position before pressing that button to engage the KA0 relay. Looks like only danger is motor would start as soon as button is pushed if switch was left in 1 or 2 position.

Lil Foot · Feb 25, 2020

It doesn’t look like that switch will work. You definitely need connections in the 0 position. I’m sure it could be rigged to work, but it would defeat the safety of making sure the switch was in the 0 position before pressing that button to engage the KA0 relay. Looks like only danger is motor would start as soon as button is pushed if switch was left in 1 or 2 position.

I was afraid of that, kinda hoping I was just missing something.
Guess I will start the search all over again. Sigh.
Thanks.

dochsml · Feb 25, 2020

Lil Foot said:
I was afraid of that, kinda hoping I was just missing something.
Guess I will start the search all over again. Sigh.
Thanks.

I'm not entirely sure why they put such a big amperage switch. All it is doing is powering the coils of the motor contactors. If you wanted to go cheap, you could put a blank off plate where this switch mounted and replace it with a much smaller 3 position toggle switch. You would then switch it one way for CW and the other way for CCW with middle being '0'. The coils are actually 110V according to that wiring diagram you posted. Would just need to see what model KM1 and KM2 were to know how many amps the coils actually draw. I can't imagine it would be much.

Lil Foot · Feb 25, 2020

I thought about something like that, but would really like to keep the current control setup.
In the pic below, the lever (green arrow) is off in the middle, reverse when lifted, and forward when lowered. It turns the rod (red arrow) which operates the switch in the little box. (yellow arrow)

I have found posts on machinist forums describing this exact problem on my exact machine, and either no one has found a solution, or they found a switch which is no longer available. All the posts I found were from 2002- 2012.

seanbarr · Feb 25, 2020

Does the old switch work at all or intermittently? I would ohm out the contacts so the circuit is mapped and do the same for the new switch. In my hands, I can figure this out but remotely, need more info.

The schematics shows 4 pole, single throws but I think operates like a double throw with a center off. (Am I correct?) Half of the switch operates two of the throws and the other half does the other set. I believe the jumpers are used to bridge the three contacts together going to the motor. There should be another similar jumper not seen.

Sent from my iPhone using Tapatalk

dochsml · Feb 25, 2020

Lil Foot said:
I thought about something like that, but would really like to keep the current control setup.
In the pic below, the lever (green arrow) is off in the middle, reverse when lifted, and forward when lowered. It turns the rod (red arrow) which operates the switch in the little box. (yellow arrow)

I have found posts on machinist forums describing this exact problem on my exact machine, and either no one has found a solution, or they found a switch which is no longer available. All the posts I found were from 2002- 2012.

You can try C3 Controls.

https://www.c3controls.com/

I don't have any experience with them, but they look like they may have something they can match up for you if you call them. What you are looking for is a cam switch.

North Idaho Wolfman · Feb 25, 2020

Lil Foot said:
The original switch checks as follows:

Old Switch

***8220;1***8221; position T1 connects to T2

***8220;0***8221; position T3 connects to T4

***8220;2***8221; position T5 connects to T6

next two pics show old switch as wired:

Were these measurements with the jumpers in place?
If they were, can you do another measurement with the jumper out?
Is it attached to the lathe like the one in this ebay ad?
https://www.ebay.com/itm/HZ5B-10-2-...athe-Replacement-Spindle-Switch-/282705625400
If it is, maybe send him a message and ask for connection diagram?

Here is a forum that he did use what you are using, maybe this will help.
https://metalworkforums.com/f309/t199703-replacing-lathe-fwd-rev-switch-hz5b

BruceP · Feb 25, 2020

I am pretty good at electronics (for over 40 years).... But I am still jealous that you have an engine-lathe.

For the record.... to change rotation-direction of a 3-phase motor, ANY TWO wires feeding the motor need to be swapped.

dochsml · Feb 25, 2020

seanbarr said:
Does the old switch work at all or intermittently? I would ohm out the contacts so the circuit is mapped and do the same for the new switch. In my hands, I can figure this out but remotely, need more info.

The schematics shows 4 pole, single throws but I think operates like a double throw with a center off. (Am I correct?) Half of the switch operates two of the throws and the other half does the other set. I believe the jumpers are used to bridge the three contacts together going to the motor. There should be another similar jumper not seen.

Sent from my iPhone using Tapatalk

It's a 3 pole selector switch. Three positions 1 - 0 - 2. Position 1 goes one way and position 2 goes another way. The problem is that position 0 needs its own electrical connection for it to work safely.

North Idaho Wolfman · Feb 25, 2020

Check out the diagrams of the switches the 4 position switch should work you just disregard one position.

https://www.aliexpress.com/item/328...1.0&pvid=88089988-2eb2-42ca-941d-d45c09844bba

I'm also wondering if the switch you already have, has the ability to have the wipers and stops swapped to reconfigure it?

dochsml · Feb 25, 2020

North Idaho Wolfman said:
Check out the diagrams of the switches the 4 position switch should work you just disregard one position.

https://www.aliexpress.com/item/328...1.0&pvid=88089988-2eb2-42ca-941d-d45c09844bba

I'm also wondering if the switch you already have, has the ability to have the wipers and stops swapped to reconfigure it?

I was actually going to suggest a 4 position switch if a 3 position couldn't be found. I didn't ask if the original switch was 60 or 90 degree throw. Probably want to match that up as well if you want the same feel on the lever throw.

dochsml · Feb 25, 2020

Found this that looks like it could possibly work if the throw is the angle you want and the rod can somehow get attached and it can somehow get mounted in there..... https://www.amazon.com/Changeover-Terminals-Positions-SZW26-20-0-3-2/dp/B00NTROK8Y/ref=sr_1_3?keywords=4+position+changeover+switch&qid=1582671366&sr=8-3

Could maybe wire up position 2 on this switch as the original 0 and then use 1 and 3 for CW and CCW.

North Idaho Wolfman · Feb 25, 2020

dochsml said:
Found this that looks like it could possibly work if the throw is the angle you want and the rod can somehow get attached and it can somehow get mounted in there..... https://www.amazon.com/Changeover-Terminals-Positions-SZW26-20-0-3-2/dp/B00NTROK8Y/ref=sr_1_3?keywords=4+position+changeover+switch&qid=1582671366&sr=8-3

Could maybe wire up position 2 on this switch as the original 0 and then use 1 and 3 for CW and CCW.

Yea, that was the one I was looking for, for him!

Lil Foot · Feb 25, 2020

seanbarr said:
Does the old switch work at all or intermittently? I would ohm out the contacts so the circuit is mapped and do the same for the new switch. In my hands, I can figure this out but remotely, need more info.
The schematics shows 4 pole, single throws but I think operates like a double throw with a center off. (Am I correct?) Half of the switch operates two of the throws and the other half does the other set. I believe the jumpers are used to bridge the three contacts together going to the motor. There should be another similar jumper not seen.
Sent from my iPhone using Tapatalk

Old switch was functioning properly until it physically fell apart. It is modular and made of plastic with poorly designed clips holding the pieces together-the plastic got brittle & the switch fell apart. It functions zip tied together for testing, although it can't be re-installed that way. The NEW switch has a center off.

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