Emerson mark V motor reversing mod
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- Silver Member
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- Joined: Wed Mar 26, 2014 11:34 pm
- Location: Denver Colorado
Emerson mark V motor reversing mod
Hello, long time lurker. I've been rebuilding my old shopsmith tools over the years and want to say thanks to this community for the tips and comments. I'm presently in the middle of my scroll saw rebuild and noticed the recent comments regarding the Emerson MarkV motor reversing. Well, I did this last year.
I took photos at the time which I will share below. But first let me say that I'm crazier than most and I won't recommend this mod as its possible to brick the motor. In my case I bought a used Emerson motor off of ebay years ago to upgrade my 1960 Yuba 3/4 hp Mark V. Unfortunately, the motor had a bent shaft and showed signs of overheating as the nylon winding ties were partially melted.
Bill M. here sold me a replacement shaft with new bearings and I was finally able to finish this upgrade. Many thanks to Bill for the spare part.
Anyway, Inspecting the windings on my Emerson, I noticed that I could see the connection where the wires were joined. I used an ohm meter to be sure the connection I could see was the one that needed to be separated for reversing, its the yellow wire:
The hard part is to pick/pry/separate the yellow wire from the winding without damaging the insulation. I have plenty of dull picks and plastic utensils for doing this:
I used a hobby knife to cut/split open the protective cover in the above photo. Then I cut the smaller gauge wire to bring the other side of the start winding out so it can be configured for either forward or reverse.
Then its a simpler matter of packing the winding back in so it won't rub against the rotating parts. I was paranoid that I may have nicked the insulation doing this operation, as you should be if you try this. My eyes are not as good as they used to be and inspecting things closely with an eye loupe I couldn't tell the difference between melted nylon ties or actual nicks. So I decided to cover the area with a product called Corona Dope. Its for insulating windings on high voltage coils. I used this product to recondition a high frequency adapter that I put back into service for use with my arc welder.
Here is a photo with the hard part over with. Start coil is now separated and ready for wiring up to a switch.
I wanted a semi neat job on the back to add in the wires and I found some terminals at Radio Shack that seemed to be good enough (surprise ).
Here is the final reworked board, packed with the new terminals and extra wires that exit the housing to a reversing switch.
At this point things were plugged in for the acid test. It all worked out, whew. So I decided to make a mount to hold a better, more durable reversing switch where I can reach with the inspection cover off of the headstock (unplug before sticking hand into headstock:D ).
That's how its done. I've been a happy camper since then.
I took photos at the time which I will share below. But first let me say that I'm crazier than most and I won't recommend this mod as its possible to brick the motor. In my case I bought a used Emerson motor off of ebay years ago to upgrade my 1960 Yuba 3/4 hp Mark V. Unfortunately, the motor had a bent shaft and showed signs of overheating as the nylon winding ties were partially melted.
Bill M. here sold me a replacement shaft with new bearings and I was finally able to finish this upgrade. Many thanks to Bill for the spare part.
Anyway, Inspecting the windings on my Emerson, I noticed that I could see the connection where the wires were joined. I used an ohm meter to be sure the connection I could see was the one that needed to be separated for reversing, its the yellow wire:
The hard part is to pick/pry/separate the yellow wire from the winding without damaging the insulation. I have plenty of dull picks and plastic utensils for doing this:
I used a hobby knife to cut/split open the protective cover in the above photo. Then I cut the smaller gauge wire to bring the other side of the start winding out so it can be configured for either forward or reverse.
Then its a simpler matter of packing the winding back in so it won't rub against the rotating parts. I was paranoid that I may have nicked the insulation doing this operation, as you should be if you try this. My eyes are not as good as they used to be and inspecting things closely with an eye loupe I couldn't tell the difference between melted nylon ties or actual nicks. So I decided to cover the area with a product called Corona Dope. Its for insulating windings on high voltage coils. I used this product to recondition a high frequency adapter that I put back into service for use with my arc welder.
Here is a photo with the hard part over with. Start coil is now separated and ready for wiring up to a switch.
I wanted a semi neat job on the back to add in the wires and I found some terminals at Radio Shack that seemed to be good enough (surprise ).
Here is the final reworked board, packed with the new terminals and extra wires that exit the housing to a reversing switch.
At this point things were plugged in for the acid test. It all worked out, whew. So I decided to make a mount to hold a better, more durable reversing switch where I can reach with the inspection cover off of the headstock (unplug before sticking hand into headstock:D ).
That's how its done. I've been a happy camper since then.
- JPG
- Platinum Member
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- Joined: Wed Dec 10, 2008 7:42 pm
- Location: Lexington, Ky (TAMECAT territory)
Thank You indeed!!!!!!!!!!!!!!
I have a funky motor that I will have to take a look at!
I have a funky motor that I will have to take a look at!
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Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
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Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
- rcplaneguy
- Platinum Member
- Posts: 549
- Joined: Mon Sep 23, 2013 6:33 pm
- Location: Chapel Hill, NC
Nice job. I have not been able to see or find an internal connection on the Emerson motors that I have rebuilt. Yes, if you can get to the connection where the 2 run windings and a start winding wires are connected, then you can make the motor reversible. I just did a GE 3/4 HP motor this week where this connection was on top of the coil windings. Only had to cut 2 wrappings and used 1 tie wrap after cutting the start winding wire (smaller than the 2 run windings wires) and soldering a external lead to the start winding wire.
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Bill Mayo bill.mayo@verizon.net
Shopsmith owner since 73. Sell, repair and rebuild Shopsmith, Total Shop & Wood Master headstocks, SPTs, attachments, accessories and parts. US Navy 1955-1975 (FTCS/E-8)
Shopsmith owner since 73. Sell, repair and rebuild Shopsmith, Total Shop & Wood Master headstocks, SPTs, attachments, accessories and parts. US Navy 1955-1975 (FTCS/E-8)
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- Silver Member
- Posts: 17
- Joined: Wed Mar 26, 2014 11:34 pm
- Location: Denver Colorado
I must have been very lucky. I've only seen one Emerson Mark V motor, this one, and it just so happens that the wires needing modification for reversing were somewhat accessible.
If Bill Mayo hasn't seen a similar wiring configuration among the many Emerson motors that have been on his bench, then it must be rare to have this condition.
Don't do any exploratory surgery to do the reversing mod on an otherwise good motor:D
If Bill Mayo hasn't seen a similar wiring configuration among the many Emerson motors that have been on his bench, then it must be rare to have this condition.
Don't do any exploratory surgery to do the reversing mod on an otherwise good motor:D
- JPG
- Platinum Member
- Posts: 34632
- Joined: Wed Dec 10, 2008 7:42 pm
- Location: Lexington, Ky (TAMECAT territory)
Oh I think you have provided a road map for locating that splice.dj1960gold wrote:I must have been very lucky. I've only seen one Emerson Mark V motor, this one, and it just so happens that the wires needing modification for reversing were somewhat accessible.
If Bill Mayo hasn't seen a similar wiring configuration among the many Emerson motors that have been on his bench, then it must be rare to have this condition.
Don't do any exploratory surgery to do the reversing mod on an otherwise good motor:D
Yes one travels that route at their own risk.;)
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Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
╟JPG ╢
╚═══╝
Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange