As far as running both at once, use a double slot drive pulley with the accessory pulleys at staggered lengths. then just throw on the extra belt when needed. I have a similar arrangement on an air compressor but one compressor with a gas engine on one side and an electric motor on the other. The only difference is I never need to operate both drives at once but I could I wanted to.
I think Gary and I are going in the same direction on this one - no clutches necessary. Just as in a generator or alternator in a car. If you aren't drawing any current from it, the only load on the driving engine is due to belt and bearing friction.
John Martin
Ah, mea culpa once again. I didn't read his reply carefully enough and fell back into "clutch" mode. But by not energizing the unused alternator, there would be no drag except during spinup. Great idea.
Two requests, please:
1) Please trim the quoted material if you *must* top-post.2) Please go to the more normal quoting string of "> " at the left margin, instead of "Quoted: ", which grows the line length far too much with even *one* level of quoting, let alone with two or more.
[ ... ]Note how often this has forced folding the lines, and sometimes even added a level of "Quoted: " in front of the previous level of folding? It *really* makes the quoted text harder to read.
Thank you, DoN.
Lawn and garden tractors are often used for things other than cutting grass. I've run mine for many many hours with the blades disengaged. If there is any perceptible belt wear due to that, I haven't noticed it. I did replace the belt, after 15 years, when I replaced the blades (too worn to sharpen again), but it didn't really need replacing. You have to realize that when the belt is slacked, it isn't rubbing on the drive pulley with any force, so friction is minimal.
No need, just switch off the electrical load to the generator not being used. The armature is then merely an idler shaft with negligible load.
Gary
Thank, Jon, and everyone who responded to my question about idling v belts.
To others, I am well aware that there is no appreciable load until an electrical load is placed on the generator/s. However, one load that is of concern is the inertial load when the armature/s are being spun up from a starter designed for only so much pull until the stop is reached and, of course, the additional wear on bearing/s, brushes. The engine needs to have so many revolutions before it will sustain ignition and it is a bit more difficult to attain when more load is present.
Many posted without reading the entire thread thereby, repeating what has already been said.
One day, I swear, I am going to ask what it is and sit back and watch. It should be great fun for all.
Anyway, thanks all.
Quoted: Quoted: Quoted: snipped-for-privacy@widget.com wrote: Quoted: Quoted: >I am building a widget consisting of a 5.5 h.p. lawnmower engine Quoted: >in the center of a 36" x 12" x 3/8" aluminum plate. Quoted: >On either end are a 3 kw.120 v.a.c. generator Quoted: >and a Leece-Neville 140 amp. 14 volt alternator. Quoted: >
Quoted: >This contraption will be driven by b-sized, v belts. Quoted: >What I wish is to have the ability to drive both Quoted: >simultaneously or each independently. Quoted: >
Quoted: >So, is it practical to engage the one that I want to drive Quoted: >with an idler pulley and on the UN-driven one release the Quoted: >tension on its idler pulley? Quoted: >
Quoted: >What I am asking is that is it practical to have a v belt Quoted: >that is not being used, to just be very loose in the pulley Quoted: >grooves while not being used? Quoted: > Quoted: >
Quoted: Lawnmowers certainly do this. The PTO "clutch" on my Quoted: Bolens works this way. They have two sheaves, on on the engine, Quoted: one on the PTO shaft, and a tension roller that runs against the back Quoted: of the belt to engage it. Quoted: Quoted: It may take some amount of fiddling around to keep the belt Quoted: from occasionally jumping off the pulleys. Quoted: Quoted: Jon
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.