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Utterpower PMG Q&A
Q. What Voltage does the PMG operate at? A. North American Standards allow us to operate as high as 127/254 volts, or as low as 110/220 (at the end of the distribution point). The PMG produces 127/254 at 60hz no load, and at a severe overload of 140% the PMG is still within the Spec for voltage droop, this is all done without a failure prone voltage regulator. Of course voltage droop is far better than just meeting our Standard when we observe the continuous rating of the PMG (3000 watts continuous), but the 4000 watt plus overload never seemed to get the unit very hot in our low ambient Summer temps here in Western Washington. Q. Are there any serviceable parts inside? A. Not really, the front bearing on the shaft end could be 'changed out' in the field with a few minutes of training, this can be done without pulling the rotor. In countries where there is not yet a repair facility, we plan to work with DIYers to allow them to safely change the rear bearing (requires removing the fan first). We are assembling with high grade Japanese bearings, and we expect these to run for many years before a bearing change is necessary. Q. Why do you use a tapered bushing pulley? What's the advantage? A. Taper Locks are popular in commercial applications, it makes it VERY easy to place a pulley and to remove it, even with gloves on in sub zero temps! There are several ways to install these pulleys, but I recommend that you place the pulley on the shaft, and then put the Bushing (taper lock) on the outside. Use the Metric bolts AND the metric threaded holes in the pulley to secure the pulley to the shaft. Tighten evenly, each bolt a little bit at a time in a circular pattern, and done use two hands on the wrench! No need to get the REAL tight, as they lock up pretty solid moderately tight. there is another set of bolts that are used as 'jacks' to remove the pulley, simply remove the Metric bolts, and Jack the bushing loose from the pulley in the same circular pattern. Once you experience taper locks, you'll find it hard to use anything else. One trick in installing the taper bushing, insert a screw driver in the slot, tape it in with a hammer to spread it a little, and it will slid on the shaft easy. Q. How do I check the Stator wiring, I want to be sure it's right before I run it. A. See the charts that show open circuit voltage output at rated output, verify that your stator puts out the same voltage. Q. How do I check stator wire designations? , I want to be sure they're right. A.This is a good idea, I don't expect you to find trouble with the PMGs, but I have found several ST generator heads with the wrong designations on the leads from the factory. Here's how I quickly test and wire PMGs. Use a 12 volt light bulb, an incandescent tail light bulb or similar is all you need to make the basic checks and then wire correctly. Start with all leads separated, if any are strapped together, then remove the straps. You can find the ends of the windings by putting the light bulb across them, a simple twist of the shaft, (do it fast), and the bulb will light bright. Find both Stator windings one at a time. Note, if you short the ends of one winding together, it's hard to turn the shaft! 1-////////////-2 should be the first winding. 3-////////////-4 should be the second winding After you've proven the above combinations light your 12 volt incandescent bulb connect up the following 1-////////////-23-////////////-4 (make sure 2 and 3 are strapped together With the above configuration, place your 12 volt bulb across one and four, give the shaft the same quick twist, the 12 volt light bulb should get a lot brighter! If this is not the case, swap 1 and 2 and try again. Notice that the setup above is what you'll use for 120/240 service, 2 and 3 strapped together become your neutral. You will also note that only half the load (approximately 1500 watts can be carried between neutral and either terminal 1 or 2 in this configuration, this is typical of all generators wired for 120/240 single phase operation. If you will be using your PMG for 120 volt only, arrange the windings in the following configuration 1-////////////-2 In the above configuration, the two stator windings are in parallel, and the full 3000 watts can be supported, this is necessary when you have one LARGE single 120 VAC load. Put your light bulb across these pairs and give it a twist, if you had the two windings opposing each other, the shaft should be hard to turn. If this were the case, you'd swap 3 and 4 and try again. It should now be obvious a person could lose all the designations, and quickly sort out the leads..
Q. How do I wire in a fuse box, or breaker panel? A. See the ST pages, how you wire it should be the same except for breaker sizing and lead designations.
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