Press Pulley Woes

We are having some issues getting our motor driven press to run at a reasonable speed. We run a 12x18 new style Chandler and Price that recently had its feeder system removed. We have pretty much narrowed the speed issue down to the size of our pulley.

Since the 15 inch pulley was used with the feeder system there is no longer the same resistance that there was with the feeder system and the press runs too fast even with our Kimble variable speed motor.

We have heard of reduction drive systems and reducing the drive pulley diameter, but wouldn’t it be easier to simply hook a larger diameter pulley (24 inch) to the press to fix the problem?

The only problem with the larger pulley in our experience is difficult to find. If anyone knows of a source for these pulleys we would sincerely appreciate it.

We are a non-profit historical press in Darien, Georgia

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An intermediate shaft with a stepped pulley would be easier than a larger pulley. I am in the same situation, and have the same plan.

Either a smaller pulley on the motor or a larger pulley on the press would help. If you want to go the large pulley route you might try contacting John Horn in Little Rock to see if he has any. It would probably cost a small fortune to ship, but it would get the job done.

Justin’s suggestion of an intermediate shaft would be a lot cheaper but a little more work. Plus the stepped pulley would give you somewhat variable speed (especially when combined with the Kimble motor).

The other solution would be to get a new motor and variable frequency drive. This would give a stepless variable speed range (safer for anyone not familiar with the machine). The whole thing would probably cost about $150 or less if you’re comfortable with basic wiring.

Hope this helps,

I thought a frequency drive needs a three phase motor. Is an intermediate shaft the same idea as a reduction pulley system? Thanks.

Or you could get a large belt and drive on the flywheel (ca. 48”?), which should get your lowest speed way down within easy adjustment range of the Kimble.


Nicholas Silberg et al.:

The electronics magazine in Australia has just run an article on how to build a speed controller for swimming pool filter pumps. It describes the motors suitable for use with variable-frequency motor drives and how to produce three-phase electricity from a single-phase supply. Details the limits of what the system can do. Basically, if your motor has an automatic starting switch of any kind (usually centrifugal) [and some other kinds] the motor does not like being run at reduced r.p.m. Three phase overcomes lots of problems. From memory, suitable for motors up to about 2 h.p.?

Years ago, one of my relatives had a medium-to-small business in Brisbane called “Pulleys Ltd.” which specialised in producing pulleys, especially for irrigation pumps. I am startled that there are apparently problems of working out how to use a countershaft and various size pulleys, but heard of a brickworks many years ago in this district where they installed the pulleys in the wrong relationship and had clay bricks flying all over the place.

Looks like many printers could use stepped pulleys and a speed control of motor which allows small variations of speed? But don’t overdo it; one of my friends had to point out that running a motor at one-twentififth of its rated speed (2Hz instead of 50 Hz) and expecting the same horsepower just doesn’t work.