50 cycle vs 60 cycle

[reible]

Hi,

Just doing a little reading here and noticed there was some discussion on this subject. Since earlier this year some of us had take then time to read through the online version of the PTWFE I knew right where I had seen some information.

Check:
http://www.shopsmith.com/academy/introd ... speedchart

Ed

[JPG]

And yet he measured HIS tp be 5300rpm @ fast.?

[rayjack]

And yet he measured HIS tp be 5300rpm @ fast.?

I feel like the guy in a wheelchair who asked for a cup of tea. The man serving the tea ignored him and said to the man pushing the wheelchair "Does HE take sugar?". I realise that I am a newcomer to this forum, but it would be nice to be referred to by name, or at least my forum log-in name.

When I recalibrated my 510 I simply kept on increasing the speed until the tacho read 5300. There are obviously more revs in the motor than are used at the factory (SS) setting on FAST.

Ray

[dusty]

Ray,

Welcome to the forum. It is good to have another member join this
family. I hope that you enjoy your time with the group as much as I do.

As far as how fast your machine is rotating while running on 50 cycle power, I don't know. But, you said yours is at 5300 when set at high speed. That seems close enough to the advertised high to never be a problem.

Try to avaoid that wheel chair and have a good day.

[JPG]

I feel like the guy in a wheelchair who asked for a cup of tea. The man serving the tea ignored him and said to the man pushing the wheelchair "Does HE take sugar?". I realise that I am a newcomer to this forum, but it would be nice to be referred to by name, or at least my forum log-in name.

When I recalibrated my 510 I simply kept on increasing the speed until the tacho read 5300. There are obviously more revs in the motor than are used at the factory (SS) setting on FAST.

Ray

OK RAY! You are NOT a HE. No slight was intended!:o

The reason for my persistence is due to a total lack of understanding of how you ARE running '5300rpm' with a 50 Hz electrical source.

The PTWFE chart in the first post of this thread repeats what I originally said in the 'Dust Collection' thread where all this started.(speed ranges from 585rpm tp about 4300rpm) I did NOT come up with my initial figures by referring to a chart. I based them on the actual difference in the frequency of the electrical source.

I would like to understand HOW you 'ran up the speed until the tach indicated 5300'.

I would like to know where the outer surface of the drive belt is on the motor sheaves(how far INSIDE the outer circumference)when speed control is set to fast. I fear it may be extending out above the outside of the sheave at this setting. The belt may be running dangerously close to the bottom of the control sheave as well. In order for the sheaves to be so hyper-extended, the speed control arm would be extremely close to interfering with the rotating control sheave.

Upon examining MY own 115v/230v 50/60Hz ss motor's name plate, it indicates a rated speed of 3450/2850 at 50/60Hz. This indicates the rated slip speed of the motor is about 95% of the synchronous speed(3600/3000 rpm). This indicates the ss output shaft speed(700 to 5200) is about 0.2 to 1.5 times the motor shaft speed when operated utilizing a 60Hz electrical source. This translates to 570 to 4275 when operating at 50Hz.

As another (quite remote, but possible) explanation of your observations, What did you use as a tachometer? Was it mechanical,(sympathetic vibration) or electrical(strobe). If strobe, WHAT did it use as a reference. Some 'ancient' strobe type used the electrical source frequency as a reference. IF the strobe were calibrated ASSUMING 60Hz source, it would indicate 5300rpm when strobe is synchronized on an object rotating at 4416rpm. If you used a vibrating reed type, it may have been responding to something other than the main output shaft.

I fear the mis-adjusted speed control is also remote.(I do NOT think the mechanism CAN be stretched that far to operate 20% beyond 'normal') It could be stretched from 4275 to 4416 perhaps.

As I said at the top of this thread, I do NOT understand! The physical properties of the ss mechanism and the electrical motor do NOT possess the capability to achieve 5300rpm at the output shaft without gross mis-adjustments.

As an aha after thought, Did you by any chance use the tachometer on the 'intermediate/idler shaft? It runs 1.6 x faster than the main output shaft!(1120 to 8320 @ 60Hz or 933 to 6858 @ 50Hz) THAT would imply the speed control is mis-adjusted in the opposite direction! As an added indicator, how far from the exposed surface of the locknut does the high speed adjustment screw socket end stand proud/recessed?

Alas no obvious 'conclusion'. I be totally dependent on you RAY to provide the 'missing detail(s).

I apologize to all others in this forum if I have publicly discussed this too long and too often. I DO feel however that WE all learn from such discussions of un-understood situations.

[rayjack]

OK RAY! You are NOT a HE. No slight was intended!:o

The reason for my persistence is due to a total lack of understanding of how you ARE running '5300rpm' with a 50 Hz electrical source.

The PTWFE chart in the first post of this thread repeats what I originally said in the 'Dust Collection' thread where all this started.(speed ranges from 585rpm tp about 4300rpm) I did NOT come up with my initial figures by referring to a chart. I based them on the actual difference in the frequency of the electrical source.

I would like to understand HOW you 'ran up the speed until the tach indicated 5300'.

I would like to know where the outer surface of the drive belt is on the motor sheaves(how far INSIDE the outer circumference)when speed control is set to fast. I fear it may be extending out above the outside of the sheave at this setting. The belt may be running dangerously close to the bottom of the control sheave as well. In order for the sheaves to be so hyper-extended, the speed control arm would be extremely close to interfering with the rotating control sheave.

Upon examining MY own 115v/230v 50/60Hz ss motor's name plate, it indicates a rated speed of 3450/2850 at 50/60Hz. This indicates the rated slip speed of the motor is about 95% of the synchronous speed(3600/3000 rpm). This indicates the ss output shaft speed(700 to 5200) is about 0.2 to 1.5 times the motor shaft speed when operated utilizing a 60Hz electrical source. This translates to 570 to 4275 when operating at 50Hz.

As another (quite remote, but possible) explanation of your observations, What did you use as a tachometer? Was it mechanical,(sympathetic vibration) or electrical(strobe). If strobe, WHAT did it use as a reference. Some 'ancient' strobe type used the electrical source frequency as a reference. IF the strobe were calibrated ASSUMING 60Hz source, it would indicate 5300rpm when strobe is synchronized on an object rotating at 4416rpm. If you used a vibrating reed type, it may have been responding to something other than the main output shaft.

I fear the mis-adjusted speed control is also remote.(I do NOT think the mechanism CAN be stretched that far to operate 20% beyond 'normal') It could be stretched from 4275 to 4416 perhaps.

As I said at the top of this thread, I do NOT understand! The physical properties of the ss mechanism and the electrical motor do NOT possess the capability to achieve 5300rpm at the output shaft without gross mis-adjustments.

As an aha after thought, Did you by any chance use the tachometer on the 'intermediate/idler shaft? It runs 1.6 x faster than the main output shaft!(1120 to 8320 @ 60Hz or 933 to 6858 @ 50Hz) THAT would imply the speed control is mis-adjusted in the opposite direction! As an added indicator, how far from the exposed surface of the locknut does the high speed adjustment screw socket end stand proud/recessed?

Alas no obvious 'conclusion'. I be totally dependent on you RAY to provide the 'missing detail(s).

I apologize to all others in this forum if I have publicly discussed this too long and too often. I DO feel however that WE all learn from such discussions of un-understood situations.

All I can say is WOW!!

Give me a little while to look at all this and I'll come back to you.

Ray

[JPG]

RAY! Thank for your attention! I do hope there is a simplier/safer/less disconcerting explanation. I realize I have requested action on your part and appreciate anything you do here!

[dlbristol]

Ray Welcome to the forum! As you have seen there is a wealth of info and expertise on the forum. Most of these folks are talented on many areas, and bring some very focused and penetrating questions to you if you are trying to solve problems.
JPG, brings woodworking, SS technical and tachometer info to the table in one thread. This is the kind of info you would pay dearly for if you could find a customer service department that had the capability.
For me, reading these posts has been a quality education in itself!

[rayjack]

The PTWFE chart in the first post of this thread repeats what I originally said in the 'Dust Collection' thread where all this started.(speed ranges from 585rpm tp about 4300rpm) I did NOT come up with my initial figures by referring to a chart. I based them on the actual difference in the frequency of the electrical source.

I would like to understand HOW you 'ran up the speed until the tach indicated 5300'.

I would like to know where the outer surface of the drive belt is on the motor sheaves(how far INSIDE the outer circumference)when speed control is set to fast. I fear it may be extending out above the outside of the sheave at this setting. The belt may be running dangerously close to the bottom of the control sheave as well. In order for the sheaves to be so hyper-extended, the speed control arm would be extremely close to interfering with the rotating control sheave.

Upon examining MY own 115v/230v 50/60Hz ss motor's name plate, it indicates a rated speed of 3450/2850 at 50/60Hz. This indicates the rated slip speed of the motor is about 95% of the synchronous speed(3600/3000 rpm). This indicates the ss output shaft speed(700 to 5200) is about 0.2 to 1.5 times the motor shaft speed when operated utilizing a 60Hz electrical source. This translates to 570 to 4275 when operating at 50Hz.

As another (quite remote, but possible) explanation of your observations, What did you use as a tachometer? Was it mechanical,(sympathetic vibration) or electrical(strobe). If strobe, WHAT did it use as a reference. Some 'ancient' strobe type used the electrical source frequency as a reference. IF the strobe were calibrated ASSUMING 60Hz source, it would indicate 5300rpm when strobe is synchronized on an object rotating at 4416rpm. If you used a vibrating reed type, it may have been responding to something other than the main output shaft.
As an aha after thought, Did you by any chance use the tachometer on the 'intermediate/idler shaft? It runs 1.6 x faster than the main output shaft!(1120 to 8320 @ 60Hz or 933 to 6858 @ 50Hz) THAT would imply the speed control is mis-adjusted in the opposite direction! As an added indicator, how far from the exposed surface of the locknut does the high speed adjustment screw socket end stand proud/recessed?
I apologize to all others in this forum if I have publicly discussed this too long and too often. I DO feel however that WE all learn from such discussions of un-understood situations.

I think I can now answer your queries.

1.When I was recalibrating I turned the speed dial spindle until the tachometer, reading from a reflective spot just below the teeth on the sawblade, read 5300.
2.At the fast setting the belt on the lower sheave is 0.142” (3.61mm) below the rim. The upper is 1.72” (43.75mm) below the rim.
3.Regarding the speed control arm position being close to the control sheave, I have never experienced the screeching noise as posted by Dusty in another thread, when the arm rubs on the sheave.
4.The motor speed, read from a reflective spot on the lower sheave, is approximately 2900, which equates with your calculations of a 3000rpm speed for the 50 cycle input.
5.The Tachometer is a Photo Digital (Strobe) Tacho which I purchased cheaply on Ebay (from Hong Kong) expressly for this one-off task. There is no indication in the spec (see photo) of whether it is referenced for 50 or 60 cycles, but the answer to 3 above seems to indicate that the reading is correct.
6.As I said above, the speed was read from the sawblade, not the intermediate drive shaft.
7.The high speed adjustment screw extends only just enough to get the locking nut on.
8.As a further observation, the upper and lower pulleys seem to be the same diameter (roughly 5.5” - difficult to get a caliper in there to read accurately), but here appears to be variation in the sizes of the poly-v belt pulleys, (again difficult to measure) but I don't think there would be a special sizing here for the UK?
9.I have re-read the speeds on the sawblade at various settings, they are Fast 5287, R 3455, E 1078.
Ray

[rayjack]

The PTWFE chart in the first post of this thread repeats what I originally said in the 'Dust Collection' thread where all this started.(speed ranges from 585rpm tp about 4300rpm) I did NOT come up with my initial figures by referring to a chart. I based them on the actual difference in the frequency of the electrical source.

I would like to understand HOW you 'ran up the speed until the tach indicated 5300'.

I would like to know where the outer surface of the drive belt is on the motor sheaves(how far INSIDE the outer circumference)when speed control is set to fast. I fear it may be extending out above the outside of the sheave at this setting. The belt may be running dangerously close to the bottom of the control sheave as well. In order for the sheaves to be so hyper-extended, the speed control arm would be extremely close to interfering with the rotating control sheave.

Upon examining MY own 115v/230v 50/60Hz ss motor's name plate, it indicates a rated speed of 3450/2850 at 50/60Hz. This indicates the rated slip speed of the motor is about 95% of the synchronous speed(3600/3000 rpm). This indicates the ss output shaft speed(700 to 5200) is about 0.2 to 1.5 times the motor shaft speed when operated utilizing a 60Hz electrical source. This translates to 570 to 4275 when operating at 50Hz.

As another (quite remote, but possible) explanation of your observations, What did you use as a tachometer? Was it mechanical,(sympathetic vibration) or electrical(strobe). If strobe, WHAT did it use as a reference. Some 'ancient' strobe type used the electrical source frequency as a reference. IF the strobe were calibrated ASSUMING 60Hz source, it would indicate 5300rpm when strobe is synchronized on an object rotating at 4416rpm. If you used a vibrating reed type, it may have been responding to something other than the main output shaft.
As an aha after thought, Did you by any chance use the tachometer on the 'intermediate/idler shaft? It runs 1.6 x faster than the main output shaft!(1120 to 8320 @ 60Hz or 933 to 6858 @ 50Hz) THAT would imply the speed control is mis-adjusted in the opposite direction! As an added indicator, how far from the exposed surface of the locknut does the high speed adjustment screw socket end stand proud/recessed?
I apologize to all others in this forum if I have publicly discussed this too long and too often. I DO feel however that WE all learn from such discussions of un-understood situations.

I think I can now answer your queries.

1.When I was recalibrating I turned the speed dial spindle until the tachometer, reading from a reflective spot just below the teeth on the sawblade, read 5300.
2.At the fast setting the belt on the lower sheave is 0.142” (3.61mm) below the rim. The upper is 1.72” (43.75mm) below the rim.
3.Regarding the speed control arm position being close to the control sheave, I have never experienced the screeching noise as posted by Dusty in another thread, when the arm rubs on the sheave.
4.The motor speed, read from a reflective spot on the lower sheave, is approximately 2900, which equates with your calculations of a 3000rpm speed for the 50 cycle input.
5.The Tachometer is a Photo Digital Tacho which I purchased cheaply on Ebay (from Hong Kong) expressly for this one-off task. There is no indication in the spec of whether it is referenced for 50 or 60 cycles, but the answer to 3 above seems to indicate that the reading is correct.
6.As I said above, the speed was read from the sawblade, not the intermediate drive shaft.
7.The high speed adjustment screw extends only just enough to get the locking nut on.
8.As a further observation, the upper and lower pulleys seem to be the same diameter (roughly 5.5” - difficult to get a caliper in there to read accurately), but here appears to be variation in the sizes of the poly-v belt pulleys, (again difficult to measure) but I don't think there would be a special sizing here for the UK?
9.I have re-read the speeds on the sawblade at various settings, they are Fast 5287, R 3455, E 1078.
Ray