texaskirbyguy
Well-known member
Got a D50 or D80 with a bad motor and want more horsepower and speed?
I might just have the solution for you!
For a long time I had been wondering if a Classic 1CR motor assembly would fit into a D50 or D80 shell. The shell castings are very similar around the motor but the 1CR motors are more powerful (6 amp vs 5 amp) and thus have more windings. I have heard here and there that they do not interchange but they LOOK so very CLOSE!
The mad scientist in me (sitting on a pile of old 1CR motors) set out to try this transplant, and it worked out very well (with a few modifications of course).
Engineering notes:
The field is inserted into the casting with the wiring at the REAR of the shell. In the 1CR the wiring is at the front. In other words the field will be flipped around.
The field is a tight fit and the way the wiring exits the side may hinder its installation. However, with some gentle finness, it will fit. I would recommend a fiberboard insulator be inserted between the casting and wires to help protect the wires.
The field is slightly longer than the D50/D80 one. Therefore the field screws from the 1CR will need to be used as they are longer.
The headlight wiring will be a tight squeeze though the holes in the casting (due to the longer field), but it will fit.
Rotor and bearing plate assembles as normal.
So for the modifications...
Mod 1 - Motor wiring for yellow, red, and green will need to be extended another few inches to make it to the safety switch.
Mod 2 - Top and bottom brushes MUST be wired OPPOSITE of the D50/D80. Some wiring extensions will be required.
**Failure to do this may cause major damage!** The rotor will run in reverse, spin the fan off until it contacts the fan case, the motor jams to a high-speed halt and strips the threads in the fan and/or on the shaft in the process. Therefore getting this right is VERY important. Just to be safe, you may want to do a quick test run without the fan installed just to verify rotation direction.
Mod 3 (optional) - Carbon brushes for 1CR are the WIDE style (first year for them) to handle more current when run on high speed. Brush holders for 1CR require a 5/8" hole. The small brush holders on D50/D80 require a 1/2" hole. Therefore you have two logical options...
Option 1 - Do not change brush holders and use D50/D80 brushes and holders. If going this way, you will want to disable high speed (with wiring mods) so that the current does not exceed much over 5 amps, which the small brushes can handle. Also the brush lead clips will need to be modified to fit the thinner, narrower slots in the holders. If you do not use the hose much, this will be the preferred, easier route.
Option 2 - Drill the casting holes out to 5/8" so the 1CR brush holders can be installed. Doing this will require a 5/8" metal cutting bit, a drill press and a good vice to securely hold the casting straight and secure. You will need a very slow feed speed and some lube on the bit. After installing the holders, you will need to seat the brushes on low speed at no load for about 20 minutes, making sure there is no excess sparking. After this you can use high speed with the hose to your heart's content.
CAUTION: During testing of high speed, make sure fan case is fully assembled and a hose is attached to the front to prevent current overload.
A healthy 1CR motor will draw 5.5 to 6 amps on high when assembled with a hose attached. Current on the rating plate is 6A.
With motor unit assembled and run without a hose, the increased airflow will cause extra loading on the motor. Current draw will be between 7.5 and 8 amps, causing overheating, excessive carbon brush arcing and commutator discoloration.
This unique motor requires the hose to restrict airflow and raise static pressure. The motor thus spins faster due to less load and current consumption is reduced to engineered specs. The redesigned motors used in Kirbys after 1CR do not have this problem to this extent.
Low speed may be safely tested with or without the rug nozzle, as current draw with the nozzle is 4.3 to 5.3 amps. Without the nozzle, it may be only .2 amps higher, as the nozzle is not very restrictive.
Picture 1 shows the 1CR motor in 1CR casting
Picture 2 shows the 1CR motor parts removed from the casting. Note the correct Kirby part numbers for this model
Picture 3 shows 1CR field installed in D50. Note tight headlight wire clearance.
Picture 4 shows tight field wiring. An insulator between casting and wires is recommended.
Picture 5 shows 1CR rotor installed. Use same bearings, clearances is all the same between D series and 1CR.
Picture 6 & 7 shows assembled modified D50 having passed electrical tests. The wiring has NOT been finalized - it is in prototype mode... However this is a good guide to the normal wiring path. (Note that headlight was not wired up)
I might just have the solution for you!
For a long time I had been wondering if a Classic 1CR motor assembly would fit into a D50 or D80 shell. The shell castings are very similar around the motor but the 1CR motors are more powerful (6 amp vs 5 amp) and thus have more windings. I have heard here and there that they do not interchange but they LOOK so very CLOSE!
The mad scientist in me (sitting on a pile of old 1CR motors) set out to try this transplant, and it worked out very well (with a few modifications of course).
Engineering notes:
The field is inserted into the casting with the wiring at the REAR of the shell. In the 1CR the wiring is at the front. In other words the field will be flipped around.
The field is a tight fit and the way the wiring exits the side may hinder its installation. However, with some gentle finness, it will fit. I would recommend a fiberboard insulator be inserted between the casting and wires to help protect the wires.
The field is slightly longer than the D50/D80 one. Therefore the field screws from the 1CR will need to be used as they are longer.
The headlight wiring will be a tight squeeze though the holes in the casting (due to the longer field), but it will fit.
Rotor and bearing plate assembles as normal.
So for the modifications...
Mod 1 - Motor wiring for yellow, red, and green will need to be extended another few inches to make it to the safety switch.
Mod 2 - Top and bottom brushes MUST be wired OPPOSITE of the D50/D80. Some wiring extensions will be required.
**Failure to do this may cause major damage!** The rotor will run in reverse, spin the fan off until it contacts the fan case, the motor jams to a high-speed halt and strips the threads in the fan and/or on the shaft in the process. Therefore getting this right is VERY important. Just to be safe, you may want to do a quick test run without the fan installed just to verify rotation direction.
Mod 3 (optional) - Carbon brushes for 1CR are the WIDE style (first year for them) to handle more current when run on high speed. Brush holders for 1CR require a 5/8" hole. The small brush holders on D50/D80 require a 1/2" hole. Therefore you have two logical options...
Option 1 - Do not change brush holders and use D50/D80 brushes and holders. If going this way, you will want to disable high speed (with wiring mods) so that the current does not exceed much over 5 amps, which the small brushes can handle. Also the brush lead clips will need to be modified to fit the thinner, narrower slots in the holders. If you do not use the hose much, this will be the preferred, easier route.
Option 2 - Drill the casting holes out to 5/8" so the 1CR brush holders can be installed. Doing this will require a 5/8" metal cutting bit, a drill press and a good vice to securely hold the casting straight and secure. You will need a very slow feed speed and some lube on the bit. After installing the holders, you will need to seat the brushes on low speed at no load for about 20 minutes, making sure there is no excess sparking. After this you can use high speed with the hose to your heart's content.
CAUTION: During testing of high speed, make sure fan case is fully assembled and a hose is attached to the front to prevent current overload.
A healthy 1CR motor will draw 5.5 to 6 amps on high when assembled with a hose attached. Current on the rating plate is 6A.
With motor unit assembled and run without a hose, the increased airflow will cause extra loading on the motor. Current draw will be between 7.5 and 8 amps, causing overheating, excessive carbon brush arcing and commutator discoloration.
This unique motor requires the hose to restrict airflow and raise static pressure. The motor thus spins faster due to less load and current consumption is reduced to engineered specs. The redesigned motors used in Kirbys after 1CR do not have this problem to this extent.
Low speed may be safely tested with or without the rug nozzle, as current draw with the nozzle is 4.3 to 5.3 amps. Without the nozzle, it may be only .2 amps higher, as the nozzle is not very restrictive.
Picture 1 shows the 1CR motor in 1CR casting
Picture 2 shows the 1CR motor parts removed from the casting. Note the correct Kirby part numbers for this model
Picture 3 shows 1CR field installed in D50. Note tight headlight wire clearance.
Picture 4 shows tight field wiring. An insulator between casting and wires is recommended.
Picture 5 shows 1CR rotor installed. Use same bearings, clearances is all the same between D series and 1CR.
Picture 6 & 7 shows assembled modified D50 having passed electrical tests. The wiring has NOT been finalized - it is in prototype mode... However this is a good guide to the normal wiring path. (Note that headlight was not wired up)
