MEP 803a frequency and load meter inacurate

[off the wall]

I am looking for information on diagnostic information on the frequency and load meters for my MEP 803a . the frequency meter will read anywhere from 61 Hz to 65Hz while actually running at 60.5 Hz as confirmed by a Fluke meter. and the load meter will read ~50% while running on a 240v 7500 (31amp) watt electric heater also confirmed by a fluke meter. the volt meter is accurate.

 

[kloppk]

Have you tested the Frequency Transducer and Freq Meter per the -24 TM? Results?
TMs are here ---> 803 TMs

 

[Scoobyshep]

The OEM meters are more of a guideline than an actual reading.

 

[LuckeyD]

These are analog meters unless you are running a digital system like AMMPS and the 30/60KW B models. Analog meters are most accurate in the mid ranges. F type calibration set 101 I learned the hard way. I always first used my DMM in the outlet and then adjusted the gages in mid range area to my DMM, which I got calibrated regularly.

In short, NO. They are not accurate. They are close. Mr. Scoobyshep hit it on the button. In order of accuracy seemed to be; %rated load the worst, then the amp gages if separate(when compared to an amp probe with math sometimes), then volt meters, and most accurate at about 5% off accuracy in worst case were the freq gages in 60 Hz. They were off in the norm at 2.5 hertz. The small black screw looking button on the gage when adjusted slightly and slowly can bring most to what your DMM says adjusting the mechanical works. They were never meant to be calibrated so close was good enough in most cases. 400Hz were the most accurate. The advent of digital systems allowed the engines to run at the best and most steady 1800 rpm for normal 60Hz gens. Before this gens were thought of as utility gens and accuracy was not as important. Close was good enough. Hope this answers your question.

 

[Guyfang]

@LuckeyD wrote:
Before this gens were thought of as utility gens and accuracy was not as important. Close was good enough.

And that's why we had Utility Generator sets, and Precise generator sets. And using the word Precise, always entailed smirking a bit. Small generators are not meant to be precise. Just close enough for Government work. The first paragraph of Lucky's post, says it all. Do that and you will have not doubts "about whats coming out.

 

[LuckeyD]

I tried to explain it. Precise sets were usually provided for only certain systems, support systems, and hospitals. Then TQGs came out and they still did not have them really accurate. Had every one just a bit off I worked on. That was several thousand 15-60KWs. Again the 400HZ systems were more accurate. The DMM is pretty close. About 25% of the 30-60KW B models are also not accurate. We were provided factory extender cables to adjust the back planes so we could get them accurate again. This way the screens say what a DMM would read. So set your TQG with a DMM, read what you have and then you know the setting.

Oh, try this one. Do you really believe you have 120VAC at 60Hz from the power company? Take measurements at different times of the day and see at a wall outlet. Your gen when adjusted will be similar, or even more steady. Here i am supposed to have 220VAC at 50 Hz. Nope. 217-230VAC time dependent, at 49-51 Hz grid compensation dependent. At 1:36AM I have 233VAC and 49.99 Hz in my kitchen. Station transformer is across the street in the church yard. It is fed 254,000 VAC under ground so no poles. I asked when the power folks were there. Check yours. In Maryland I had 58-61 Hz 1 mile from a central power station distribution station for industrial plants at 115 to 130VAC. The 240 swung from 225-245VAC. This is acting thru the transformer taking 15,200 off the line to two houses. There are peaking transformers to 440VAC, on MCM 2 lines to an industrial plant and at higher voltages the difference is not too much. Same results at the military installation I worked on. Sensitive buildings had compensation AC inputs. Helps to understand what you are actually using in your house and paying for. Interesting. This does not effect what the meter does so you pay for what you use.

 

[off the wall]

I tried to explain it. Precise sets were usually provided for only certain systems, support systems, and hospitals. Then TQGs came out and they still did not have them really accurate. Had every one just a bit off I worked on. That was several thousand 15-60KWs. Again the 400HZ systems were more accurate. The DMM is pretty close. About 25% of the 30-60KW B models are also not accurate. We were provided factory extender cables to adjust the back planes so we could get them accurate again. This way the screens say what a DMM would read. So set your TQG with a DMM, read what you have and then you know the setting.

Oh, try this one. Do you really believe you have 120VAC at 60Hz from the power company? Take measurements at different times of the day and see at a wall outlet. Your gen when adjusted will be similar, or even more steady. Here i am supposed to have 220VAC at 50 Hz. Nope. 217-230VAC time dependent, at 49-51 Hz grid compensation dependent. At 1:36AM I have 233VAC and 49.99 Hz in my kitchen. Station transformer is across the street in the church yard. It is fed 254,000 VAC under ground so no poles. I asked when the power folks were there. Check yours. In Maryland I had 58-61 Hz 1 mile from a central power station distribution station for industrial plants at 115 to 130VAC. The 240 swung from 225-245VAC. This is acting thru the transformer taking 15,200 off the line to two houses. There are peaking transformers to 440VAC, on MCM 2 lines to an industrial plant and at higher voltages the difference is not too much. Same results at the military installation I worked on. Sensitive buildings had compensation AC inputs. Helps to understand what you are actually using in your house and paying for. Interesting. This does not effect what the meter does so you pay for what you use.

Thanks for your reply . Misteriously the freq. meter is now within the range noted in a previous post, it is reading 61~62 while actually at 60.2 it was reading full scale? the load meter reads 55~60 when it should read 70% assuming 100% is 10KW? I have heard that these will run 12 KW all day no problem, but I would like to know the momentary surge that these can handle (inductive loads, electric motors)?

Thanks again the information obtained here has been very helpfull,

 

[LuckeyD]

You got a 10KW gen. Some folks push things and then when it starts to do funny things they sell them, after asking for assistance. Then boast about it. Over 100% you run the risk of coil swell in the main gen, regulator issues, and don't forget, these are old gens. The hour meter is secured by 3 screws if I remember. Push a gen too hard too long and it can get expensive. They can take a momentary surge as long as it goes back quickly, but it does 10KW. Usually it does its full load all day. The closer to full load the less the surge you can get it to achieve. There used to be a current chart data plate on it. This should be the guide to use. On 120/240 it should say about 52 amps per phase; 120 it should say 104 amps, and on 3 phase 34 amps per phase. Check connections to things and make sure things are not corroded. Load terminals are tight, and it is grounded and you'll do fine. This makes the gen run as it should. This and normal services at about 250 hours of operation keeps it going with minimal costs for parts.

 

[Guyfang]

Everyone is obsessed with how far they can overload a gen set. You would not want to drive your car at 130 MPH all day. Bet it would die soon. If you want more than 10 KW, buy a 15 KW.

 

[Scoobyshep]

That novelty comes from the consumer Gen market. When they say 10k it's surge. They really run at 8k. Just cause you can doesn't mean you should

 

[2Pbfeet]

I tried to explain it. Precise sets were usually provided for only certain systems, support systems, and hospitals. Then TQGs came out and they still did not have them really accurate. Had every one just a bit off I worked on. That was several thousand 15-60KWs. Again the 400HZ systems were more accurate. The DMM is pretty close. About 25% of the 30-60KW B models are also not accurate. We were provided factory extender cables to adjust the back planes so we could get them accurate again. This way the screens say what a DMM would read. So set your TQG with a DMM, read what you have and then you know the setting.

Oh, try this one. Do you really believe you have 120VAC at 60Hz from the power company? Take measurements at different times of the day and see at a wall outlet. Your gen when adjusted will be similar, or even more steady. Here i am supposed to have 220VAC at 50 Hz. Nope. 217-230VAC time dependent, at 49-51 Hz grid compensation dependent. At 1:36AM I have 233VAC and 49.99 Hz in my kitchen. Station transformer is across the street in the church yard. It is fed 254,000 VAC under ground so no poles. I asked when the power folks were there. Check yours. In Maryland I had 58-61 Hz 1 mile from a central power station distribution station for industrial plants at 115 to 130VAC. The 240 swung from 225-245VAC. This is acting thru the transformer taking 15,200 off the line to two houses. There are peaking transformers to 440VAC, on MCM 2 lines to an industrial plant and at higher voltages the difference is not too much. Same results at the military installation I worked on. Sensitive buildings had compensation AC inputs. Helps to understand what you are actually using in your house and paying for. Interesting. This does not effect what the meter does so you pay for what you use.

thanks for the humor.

Yes, I see lots of folks obsessing about the power quality of their generators, without the perspective of having checked their grid power quality. Depending on where you live, and what else is on your particular distribution circuit the power quality can be all over the map. An electrician I know used to live a mile or so beyond a golf course (wells, and distribution pumps), that was a mile or so from a metal fabricating shop (heavy duty presses, welders, rotary hammers, punches, etc., but only M-F) The voltage at his place was all over the map, and then folks started adding home solar that started driving the voltage around even more, and adding extra harmonic distortion from the inverters. Finally the utility relented and added an automatic voltage regulator just beyond the metal shop, and another just beyond the golf course, and life, as far as the power instabilities, settled down. When my neighbor down the road here added a budget solar system, the grid THD just exploded, despite several transformers between us. Jeesh. I highly doubt that their inverters meet the FCC and grid requirements for quality.

I've lived in a number of places around the US, and elsewhere, and I haven't been fortunate enough to live in more than one or two places that had high quality grid power.

The power from my MEP-803A is better than what comes across my meter, and by better, I mean lower THD, better voltage regulation, and for our uses, nearly equivalent frequency stability, and that was after the utility removed a capacitor bank that was really pushing our distribution circuit around. I suspect that our distribution circuit would benefit from a couple of automatic voltage regulators, but the utility is pretty miserly about installing them because of the capital costs and also the ongoing replacement costs as they are a wear item.

All the best,

2PbFeet