Small motor help

A friend of mine has and old Herman Nelson hot water heater (radiator type unit that looks like a propane heating unit) with a Reliance 1/6 HP 3 phase 1725 RPM fan motor that's burned out. May have lost a phase because no phase protection on the controls and 120VAC contactor coil from another source.
Motor is old and is 56G frame. It's resilient mount outer ring and rubber there but not used. It's mounted via 4 stubby U type bracket attached with the 4 studs that connect the 2 end plates to the field winding housing. Each bracket is the same width as the distance between the front and back end plates where the studs are with a single nut on each side holding it in place. (no inner nuts as the stud has to be removed to install the bracket)
What I need to find is a motor that has the same OD and the 56 frame with the same end to end distance (or shorter) at the stud locations and same bolt circle. (a long screw will work)
I have a 1/4 HP single phase 145 frame motor on an older Buffalo bench drill press that has almost the same front to back distance about 5/16" shorter (will work spacer can be made) Has the same bolt circle and OD.
Anyone have any idea how to find a motor that will fit? NEMA frame charts don't give the needed info nor can I find information on 56G. I called a Reliance dealer but he can't cross the model number found on the nameplate. 145 frame will probably work but I can't find any low HP 145 frame motors, all I find is 145T that is too big!

Frank

Frank. I would suggest you look here and see if there's anything suitable, might suggest converting to single phase in that HP, may be easier to locate something with the frame needed. Sound like a special to me being 3 phase, and those usually need rewinding to get the exact model when it's old.

HVAC Motors - Motors - Grainger Industrial Supply

SAF Ω

Hi SAF; I've looked in all the normal sites, Granger, McMaster, MSC, Kaman and others but again nothing in 56G or 145. 120/240 VAC single phase or 208/240 VAC 3 phase will work. Voltage nor phase is a problem. Motor size is important and to modify the mount will require quite a bit of work. Looking on-line I can't find any Link to Herman Nelson except one for a company in Canada that makes large portable type heating equipment. A few references to Herman Nelson are there but not to a company, a book they wrote about propeller fans is also listed. This unit has the propeller fan I assume that means it has 2 blades.
The stubby U brackets are riveted to a "spoke" that attaches to the heater unit and holds the motor so that the fan fits the cowling with very little clearance. I suggested to my friend to find a winder that will rewind the motor but most don't want to bother with one that small. I assume if something can't be found I can use my drill press motor. The base plate on my press will accept just abut anything, I have 3 of those presses and all have different motors. Only problem will be how long will my press motor last? It's working great now but to too is very old.
Frank

A few more pointers.

A motor shop will be the most expensive, unless you can find a small one the specializes in small motors, 10HP & up is considered the breakpoint for rewinding vs replacement, or specials, which is you.

A bit about frame sizes. The 2 frame sizes you listed 56, 145, are the same diameter and same shaft centerline height, from a frame chart.
The G on the end designates a special, no suffix designates standard.
Each manufacturer has their own suffix codes.

Things that can be different on specials include but not limited to:
Shaft -Diameter, length, flat or keyway, double ended, threaded.
Mounting - Bolt pattern, Stud, Stud length, spacing and length.
Rotation - Std direction of rotation, reversible or not.
HP or Speed - Can be altered, such as high start torque combined with lower running HP.

There are many hundreds of single phase units available, with stud mountings in fractional HP ratings. Very common in the HVAC industry.
Just about every hanging shop space heaters out there have a stud mounted 48 or 56 frame motor for it's fan.
Most of these are considered specials and are sold for the application with an equipment manufacturer spec number not a frame size.
Problem is without any data on the special you have, its impossible to pick a suitable replacement.
Many are not reversible, because their specific for an application, so first you need the required rotation.
If you can get the measurements and data required I'm sure that something is out there to fill the bill, but will require work looking it up.
Pictures are a great help to see what it is you have to work with.

SAF Ω

I found a single phase 48 Frame motor, same HP and RPM. Much shorter and smaller OD. Now I can make 2 rings to fit the mount and adapt it to fit the motor. Thanks for all the information, motor should be here end of the week. I did look at those HVAC stud mount motors SAF but all those I looked at had much lower RPM. This on is an enclosed air over resilient mount motor but has the screws holding the motor together extend toward the shaft so it can be stud mounted. Being much shorter and smaller OD I can make rings to mount it to the original mount that used the studs and connected to both sides, front and back, of the motor.

Frank

Frank, Glad to hear that you found some success. Good luck with the retrofit and hopefully that water heat exchanger will last as long as the new motor.

SAFΩ