Fitting a new motor on the Clarkson Mark1 - 3 Phase


I obtained a brand new 3 Phase ABB motor for next to nothing. The new 3 Phase motor was smooth and quiet, so I decided to replace the Single Phase motor I had fitted to the Clarkson.

↓ Here is the Single Phase motor that is being replaced.
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↓ Here is the 3 Phase motor after fitting. It is a small motor.
It is an ABB model M2VA63B, rated 0.25Kw at 50Hz.
The original Clarkson motors were 0.5hp. Since 1hp=0.745699Kw a 0.5hp motor is 0.37Kw.
The new motor is 0.12Kw undersized, about 33%. The motor only needs to turn a grinding wheel and I figure the power will probably be sufficient, providing I grind lightly and not too agressively. If it turns out to be a failure then I can always change it out; it is worth a try.
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↓ The bore in the Clarkson pulley did not match the diameter of the shaft on the new motor, so I had to make a sleeve to fit the pulley on the shaft. I copied the method I used when fitting the pulley to the Single Phase motor.
Here is the arrangment I used for the Single Phase motor. The sleeve fits over the motor shaft and fits inside the pulley. A 7mm hole is drilled in the sleeve. The 1/4inch BSW bolt on the pulley passes through the hole in the sleeve and locates on the bottom of the keyway.
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↓ In the lathe, I turned down the outside of the sleeve to around 15.8mm diameter, until it would just fit inside the bore of the pulley. I bored the sleeve to around 10.96mm diameter, until it would just slip over the motor shaft.
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↓ Trying the sleeve in the bore of the pulley and over the motor shaft. The hole for the holding screw has not been drilled yet.
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↓ I replaced the 1/4 inch BSW bolt with a 1/4 inch BSW socket set screw (grub screw). I turned down the end of the socket set screw so it was a nice fit in the keyway.
Here you can see the socket set screw passing through the sleeve in the pulley.
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↓ Here are some dimensions and views of the motor pulley.

Diameter of pulley, at top of crown = 76.1
Diameter of pulley, at bottom of crown = 75.1
Diameter of pulley, hub section = 44.5

Width of pulley, total = 44.5 (31.7+12.8)
Width of pulley hub section = 12.8

Width of crown, only = 28.16
Width of crown, plus the bevels either side of the crown = 31.7

↓ Note the bevels either side of the crown.
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↓ I drilled two holes in the cable box ...
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... and fitted two plastic End Fittings for the Plastic Conduit.
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The wiring is enclosed in black Plastic Conduit.
The three blacks wires are the 3 Phase supply to the motor.
The Brown and Blue wires on the left are the 240v supply to the MEM Lamp.
The Brown and Blue wires on the right are the 240v supply to the MEM Lamp.
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Here you can see the 3 Phase supply wired in Delta. The three metal links connect the top three terminals with the bottom 3 terminals (U V W).
For a neater job, I soldered an Eye Fitting to the end of each of the 3 black cables.
The 4 unconnected wires (2 blue and 2 brown) are the power supply for the MEM Lamp.
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I crimped Bullet Connectors on the ends of the MEM Lamp supply cables, and joined them up in the Motor Cable Box.
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The wiring at the motor was completed.
The Plastic Conduit on the right contains the feeds to the MEM Lamp.
The Plastic Conduit on the left contains the 3 Phase supply in to the motor, and also the Single Phase supply in for the Mem Lamp.
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Here is the Plastic Conduit entering the Mem Lamp.
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↓ Here is the VFD I am using. The wiring is not yet tidied up and enclosed.
1. The 240v Single Phase power for the VFD comes from the Switch Fused Spur that you can just see at bottom left.
2. The 240v Live (brown) and Neutral (blue) enters the VFD at terminals 1 and 3 on the left. This powers the VFD.
3. The 3 Phase 240v Lives (3 black wires) are connected to the three right hand terminals on the VFD. This is the 3 Phase supply to the motor.
4. The White flex is a permament 240v supply for the MEM Lamp on the Clarkson. I can turn off the power to the VFD and still have power to the MEM Lamp, which is very useful. A switch further down the line isolates both the VFD supply and the MEM Lamp supply.
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↓ The wiring is all straightfoward.
I re-used the wooden motor plate to mount the VFD on the wall.
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↓I programmed the VFD to give a soft start to the motor. It takes a little over 5 seconds for the motor to get to full speed (2800rpm).
Next I will make the remote control box so I can conveniently start and stop the Clarkson without having to stretch over and press the buttons on the VFD.

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