You could use a DMM to measure AC current but I buy the cheap "kill-a-watt meters" like these. I bought a couple so I could figure out why I pay so much for electric power. amazon.com/Digital-Electricity-Analyzer-Monitoring-Equipment <https://www.amazon.com/Digital-Electricity-Analyzer-Monitoring-Equipment/dp/B07M8JKLG5/ref=sr_1_5?dchild=1&keywords=watt+meter+power+analyzer&pd_rd_r=8e5003dd-620c-4df5-b104-885a67d668ac&pd_rd_w=tE52S&pd_rd_wg=h02ex&pf_rd_p=0ec05f25-9534-48fe-9c3e-40b89957230e&pf_rd_r=F8E3Y9XKR040VKDKX22C&qid=1605731765&sr=8-5> Safer than leaving AC wires exposed.
Yes, it is a kilowatt class motor but it will not draw anything close to that unless there is a mechanical load of the motor shaft. If it actually were pulling a 1000 W it could bring a bucket of water to a full boil in under two hours. For comparison, a Rheem 30 gallon domestic water heater, like the kind sold at Home Depot uses 3,800 W and That is 127 watts per gallon and your machine tool has 250 watts per gallon. I'd expect scolding hot water in minutes if the motor was in fact running near its limit. Testing with no load is not realistic possibly by a factor of 10 or more. On Wed, Nov 18, 2020 at 10:49 AM Gene Heskett <ghesk...@shentel.net> wrote: > On Wednesday 18 November 2020 12:49:21 Chris Albertson wrote: > > > How many watt hours does you motor burn if left running overnight? > > Yes I know it depends on the load and the speed. > > Cheapo induction motor, smart reprogramming of the vfd to hold up its > torque at lower speeds. I ran it at 11 g's doing the motor mount cutouts > for about 5 hours yesterday, brought the tank up to 36C, and the motor > to 38C. But slow it to 4k, where my lf boost is kicking in and it will > get hot. > > > If I did the math right and did not drop a decimal point, I think > > roughly 1 WH will heat a liter of water 1 degree C. > > > > Let's say you have a 100W motor running 8 hours that is 800 WH and you > > would expect to heat a four galon (16 liter) tank to 50C over ambient > > enough to burn your fingers and soften plastic hoses. > > Convert 1hp to watts. The motor coming is a 2.2kw model but the vfd will > limit it to less unless I reprogram it. If I have to do that, I'll > likely get a 3kw vfd. But we'll see. > > > When I ran my > > water cooler I used an old 50 gallon aquarium tank. Even with 50 gal. > > it would heat up overnight. It is pretty easy to nearly boil a > > bucket of water in 8 hours even with a small 100W heater. Even with > > a 50 gal tank I use a fan to blow air over the top of the tank. A > > primitive evaporative cooler. We were doing about 100 to 120 watts > > with 8 to 12 hour runs. Others were using trash cans filled with water > > but I just happened to have an old 50 gal tank. > > > > Do you have a water meter? I'd put one of those meters on the motor > > and calculate water heating. > > > No meter. Just stick-on lcd aquarioum thermometers that top out at 40C. > New motor is about a week away, stuck in CA customs north of the mack > bridge I expect. > > > > I > > > > On Wed, Nov 18, 2020 at 7:34 AM Gene Heskett <ghesk...@shentel.net> > wrote: > > > Greetings all; > > > > > > Leaving it run at 4g's overnight wasn't quite the result I expected. > > > > > > Going out to check on it and work on the BS-1 project, I could feel > > > the heat on my face from 3 feet away, but it was still humming along > > > at 4g's. No smoke. But the hoses on top of the motor were melted, > > > for about 3" away from the spigots on the motor. And the tank had > > > lost 3 of its 4 gallons of water with no sign of where it went, > > > nothing wet so it either came out as steam, or it melted the hoses > > > quite early and its had time to dry. Shut it down. Tank is cold. > > > Pump lost prime for lack of water at the intake. > > > > > > I think I can say that experiment was a failure. But the motor still > > > runs whisper quiet. And it looks like I need to get another big coil > > > of hose, or figure out how to pull at least 6" thru the cable chain > > > to reach the motor with "good" hose again. Plenty of spare at the > > > tank end of the run. Sigh... It, and the motor mounts, will have to > > > await the arrival of the better motor. > > > > > > Cheers, Gene Heskett > > > -- > > > "There are four boxes to be used in defense of liberty: > > > soap, ballot, jury, and ammo. Please use in that order." > > > -Ed Howdershelt (Author) > > > If we desire respect for the law, we must first make the law > > > respectable. - Louis D. Brandeis > > > Genes Web page <http://geneslinuxbox.net:6309/gene> > > > > > > > > > _______________________________________________ > > > Emc-users mailing list > > > Emc-users@lists.sourceforge.net > > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > Cheers, Gene Heskett > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > Genes Web page <http://geneslinuxbox.net:6309/gene> > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
