50 cycle vs 60 cycle

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RAY: Thank You for your effort. The belt positions are 'normal' as well as the high speed screw/nut. The motor speed should have been 2850±??? so 2900 is reasonable. I agree the tach appears reasonably accurate also. I am curious how the tach worked. You mentioned a 'reflective spot'. Did the tach 'detect' that spot by reflection?

This leaves us with the poly-v pulleys! The US(60Hz) version is 1 1/8" idler shaft and 1 3/4" main shaft diameter (OUTER circumference of the poly-v grooves). Unless your pulleys are a different size, this shall remain a mystery unless someone else 'KNOWS" and clues us in!

I TEND to agree with you re 'special' 50Hz pulleys. If they WERE different, the ratio being different would make the lower output shaft rpm slower than the 60Hz version. The pulley ratio would need to be 1.3 rather than 1.6.

Assuming a common idler pulley(1.125") the upper/main pulley would need to be about 1.5". The main pulley is the easiest to make different since it is attached to the main shaft by setscrew whereas the idler shaft pulley is a machined portion of the idler sheave.

The main shaft pulley can be fairly easily measured by looking down on it with the belt cover off. BTW was I correct re the 'extra set of mounting holes for the anti-restart switch on the belt cover? I replied to Bill Mayo that you probably did NOT like it there since it interfered with cover removal.

My pulley 'measurements' above were not exact. Eyeballed a measuring tape held against the 'top' of the pulley and looked at the od from afar.

Again THANK YOU! Good afternoon!

[rayjack]

The tachometer reads from a piece of reflective tape adhered to the sawblade.

My measurements of the belt on the two large pulleys were Lower 5.216" diameter and upper 2.18" diameter. This gives an increase on the motor speed (2900rpm)to 6931rpm at the upper pulley, which is then reduced by the poly-v belt. The lower poly v pulley is 1.1625" and the upper is 1.5" giving a reduction ratio of 0.775. 6931*0.775 = 5371, which is close to my measured speed of 5387 for the final speed.

AS I am sure you are aware I am no engineer, and my calculations may be completely wrong Please feel free to shoot me down in flames!

You were correct in your assumption that I moved the NVR switch from the belt cover as it now does not interfere with removing the cover.
I have appended rough drawings of the pullry set-up. I hope they make some sense

Ray


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EUREKA! The puzzle IS 'solved' due to your much appreciated/considerable efforts. Thank You for ALL that!

No flaming dives to-day. Your figures are most reasonable so I assume quite accurate.
YOUR MAIN SHAFT PULLEY IS DIFFERENT!

As I said in my last post, the upper pulley would have to be 1 1/2" to obtain a 1.3 ratio if all the rest was the same. GEE; that IS what you measured.(1 / 0.775) = 1.29! We can overlook the 1mm difference in our lower pulley od measurement.

This IS something to be aware of if replacing the main shaft pulley(not likely) but a possible exposure with 'used' parts.

I can't help but wonder if Ed's PTWFE chart is in later versions of the book. Since you have a ss version with a 'special' 50Hz pulley, I assume there are many others 'over there' and the chart has become unnecessary!

If you have a parts list/view in your manual, it would be interesting to know the part number.

NOW I look at the headstock parts listing, and BEHOLD! there is a different part number for 240v 50Hz!!!!!!! The pulley is NOT a separate item, but the 'domestic' drive sleeve assembly part number is 518145.
Methinks yours be different!

Again THANK YOU for all you have done to satisfy a curious old man's inquiring 'mind'. I can sleep peacefully tonight. Good Evening!