Phase Protectors and Under Volts For Pumps

[carlyai]

Lately, at about 6 pm onwards the phase protectors on my pumps operate, on/off, on/off, and sometimes full on.

I feel they are working normally as the indication 'Under Voltage' light goes on.

I have the Under Volts set a the default of 12%, which is 194 V, I think.

What is the lowest volts that my Mitsubishi 300 W and 150 W pumps can operate on without damage? Just a ball-park figure will do.

Should I set my default to 20% etc?

The trouble is it's just when 'she who must be obeyed' is about to have a shower.

When I manually over-ride the phase protector, and 'she who must be obeyed' has had a shower, the pump won't switch off.

Why won't the pump switch off when it is operating on low volts?

So, questions are:

1. What % should I set my phase protectors to?

2. Why won't the pump turn off when the supply is under voltage?

[IMHO]

Perhaps you should be looking into ways to fix the low voltage problem, rather than pushing the envelope with your pumps?

My phase protector is set to 10% tolerance. My pumps are too expensive for me to risk pushing it further.

[Crossy]

Indeed ^^^, but to answer our OP:-

220V +-10% is the limit on the supply so your pump should be happy at that. I wouldn't go much lower than -15%. Not a lot of point shelling out for protection if you override it when it does its job.

When running on low voltage the pump may not develop enough pressure to operate the pressure switch and turn off.

There are several threads on managing low voltage, perhaps a small AVR on your pump would be the answer, or a bigger one for your whole home if you have other things suffering from under voltage.

Before going and spending cash do some checks of your supply voltage at various times of day, if it's constantly low PEA could change the tapping on your transformer.

[carlyai]

Thanks,

It's only been happening for a few days, so I may try the phase protector at a higher OV percentage and get the shower done earlier.

I'll also do some voltage reading during the day.

I have the AVR's ready to go into the house system, (coming soon) but I seperated the pumps from the house system when I installed the SafeTCut to help stop false trips.

If it keeps happening I'll feed the pumps from the house system when I have it AVR protected.

[LindaLovelace]

I don't know about the mitsubishi pumps, but the guy from the Franklin distributor in Bangkok told me not to run the 2HP 15 amp submersible bore pump at less than 200V.

I ended to getting an AVR (expensive as hell) for the pump, but my undervoltage problem is gone.

Carl, what is the size of the wire coming in from the pole and how long is it? It is possible that your wire size is so small that you are getting substantial voltage drop.

I have a big cable (50mm2 copper) running into my house and little voltage drop. But like an idiot, instead of calculating the voltage drop myself, I listened to the Thai pump guy when he told me that a 90 meter run of 2.5mm2 wire for a 2hp pump would be fine. WRONG! But by the time I realized the problem the wire had been put in conduit and buried and to go up to the 10mm2 I should have put in, i'd have had to change both the wire and conduit, so I just went with an AVR at the pump end.

And for anybody that says I do not need a 10mm2 wire for a 90 meter run, I will add, the 90 meter run is from the tank house, There is another 40 meters or so of 2,5mm2 wire from the tank house to the panel in the house (not sure of the exact distance as the wire goes underground, under the house and makes some turns), so the run is really about 130 meters. 90 meters of 10mm2 coupled with 40 meters of 2.5mm2 would have worked. But the AVR works, too, and has the benefit of avoiding any fluctuation. I was getting somewhere between 20-25 total volts dropped when incoming power was normal. Enough to trip the pump control.

Edited June 8, 2015 by LindaLovelace

[RichCor]

carlyai,

What size is your reserve tank? I would hope it's large enough for 2-3 days of use with the output driven by a single-phase pressure pump.

(This would allow the main 3-phase well pump to operate during non-peak/demand time power periods to refill the reserve tank.)

Also, if only one of the phases is being dragged low, take a look at what load your household it pulling from that phase. You may want to re-balance your phase use ...though more likely the phase use issue will be upstream (and outside of your control).

You could always throw money at it... buy yet another AVR to adjust the single low phase problem child. Though, a Clay WaterJar (or plastic bin) for the bathroom area might be easier to maintain.

[Crossy]

A while back I designed a circuit to use the 'best' of the available phases to power essential single-phase loads, I'll dig it out.

You should be able to add on to the existing phase detectors so cost shouldn't be excessive.

[carlyai]

I don't know about the mitsubishi pumps, but the guy from the Franklin distributor in Bangkok told me not to run the 2HP 15 amp submersible bore pump at less than 200V.

I ended to getting an AVR (expensive as hell) for the pump, but my undervoltage problem is gone.

Carl, what is the size of the wire coming in from the pole and how long is it? It is possible that your wire size is so small that you are getting substantial voltage drop.

I have a big cable (50mm2 copper) running into my house and little voltage drop. But like an idiot, instead of calculating the voltage drop myself, I listened to the Thai pump guy when he told me that a 90 meter run of 2.5mm2 wire for a 2hp pump would be fine. WRONG! But by the time I realized the problem the wire had been put in conduit and buried and to go up to the 10mm2 I should have put in, i'd have had to change both the wire and conduit, so I just went with an AVR at the pump end.

And for anybody that says I do not need a 10mm2 wire for a 90 meter run, I will add, the 90 meter run is from the tank house, There is another 40 meters or so of 2,5mm2 wire from the tank house to the panel in the house (not sure of the exact distance as the wire goes underground, under the house and makes some turns), so the run is really about 130 meters. 90 meters of 10mm2 coupled with 40 meters of 2.5mm2 would have worked. But the AVR works, too, and has the benefit of avoiding any fluctuation. I was getting somewhere between 20-25 total volts dropped when incoming power was normal. Enough to trip the pump control.

I think my cable is OK. I have 4 single 1 X 25 m2 copper overhead, and the same equivelant al inground. My run is about 40 to 50 m.

Everything was OK until last week, thinking, thinking, then again it may not have been OK, and I may not have been aware of the problem, until I put the phase protector in.

I was aware that there is a problem in the area as we stayed in the compound in another Thai house last year, and the fluros and fans used to get pretty lazy and the fridge used to change pitch.

That is why I bought the 3 single phase AVR's which I have had so much discussion with Crossy about, and which are just waiting to go in. I think it's the next project now the garage roofing is finished.

I can't wait to get them in under test, as Crossy drew up a circuit for the 3 AvR's and I can't see how they couldn't work, but responses from manufacturers (sitting on fences), say don't do it.

The thing that has also thrown me about the AvR's is that the electrician said he tried them on the incoming phases and they didn't work. He must have done something wrong, but he's pretty good with 3 phase stuff.

So, tomorrow, hopefully, I'm going to put the AVR'S on the input to the chage over switch and leave them on 'no load' and just watch the volts meter.

Then I'm going to put them on load, minus the 3 phase water heaters.

If all successful, I'm going to rewire the pumps to feed off the AVR's because at the monemt they are seperated.

Then if everything is good, eventually I'll take the AVR's and build a cabinet near the first consumer unit from the road and install the AVR's there, and rewire the pumps to normal, so the AVR's are right on the input after the main 3 phase 65 A breaker.

[carlyai]

A while back I designed a circuit to use the 'best' of the available phases to power essential single-phase loads, I'll dig it out.

You should be able to add on to the existing phase detectors so cost shouldn't be excessive.

Sound good. Sounds like you've build electronics to sense the phase and switch between them?

Story if permitted: When I worked for Radio Aus in NT Australia commissioning our HF transmitters, we had this, well the best engineer, I have ever known. He was Russian and worked for Collins Radio Company in the States, and he designed a unit to pick the best signal, from 5 HF frequencies (you know HF broadcasting, the signals keep fading in and out), and output a constant ampitude signal, which we rebroadcast.

Don't know if you remember me but I still have these AVR's to go in, and hopefully that may fix the problem.

One thing I could have done when I put in the MOVls and installed the new DIN box, is I may now be feeding the pumps from a different phase than before.

When I install the AVR's under test tomorrow, I will know more about the incoming voltage.

I would still love to see your circuit design.

[carlyai]

Sorry, off topic, but, just tidied up my SafeTCut wiring adn am a little concerned.

I had to wire the neutral from the input of the SafeTCut to the consumer unit earth. (All tested, all works).

So I wired the 1 X 25 m2 into the neutral of the SafeTCut and then installed a special connector to join this wire with another to the consumer earth.

The trouble is I did't have a copper connector but a al connector.

Is it OK to use an aliminum connector to join two copper wires?

The connector is one of those big connectors that use a 18 spanner to do up the bolts.

[RichCor]

Problems With Aluminum and Copper Wire Electricity

by Jerry Walch, Demand Media

When Copper Meets Aluminum

While copper and aluminum can work together, they require special connectors to join these different metals. The problem begins when two dissimilar metals meet; a chemical reaction takes place that causes them to oxidize. Oxidation causes a high-resistant connection to develop with an unwanted voltage drop across the connection. Voltage drop leads to three potential problems: low voltage resulting in equipment damage, wasted energy and poor efficiency -- and the most dangerous of all -- the connection heats up and can contribute to fires at high-ampere loads.

Expansion and Contractions

Aluminum and copper do not expand and contract at the same rates as they heat up and cool down. This difference can cause wire splices or connections to work loose. A loose connection, whether at a splice in a junction box or at a terminal screw on a switch or receptacle can cause arcing. Loose connections are forerunners to arc faults, arc flash and fires in electrical systems.

Copper and Aluminum Connections

Electricians can splice copper and aluminum wires together by using special copper-aluminum connectors. You cannot splice them using a standard wire nut without dire consequences. Connectors identified with a "Cu/Al" splice contain a chemical compound that combats the oxidation that would normally take place when joining aluminum and copper. Many of these Cu/Al-splicing connectors require special tools and expert knowledge to use correctly. These connective devices require expensive tools typically beyond the reach of the average do-it-yourself person; leave them to the professionals for safe results.

Connective Devices

Modern devices when marked with Cu/Al indicate safe use with either aluminum or copper wire. But devises marked with just a “Cu” cannot be used safely with aluminum wire, as it is designated for copper use only. When a device marked “Cu” is used with aluminum wire, all the problems previously described can occur and a fire can happen at any time.

Edited June 8, 2015 by RichCor

[carlyai]

Problems With Aluminum and Copper Wire Electricity

by Jerry Walch, Demand Media

When Copper Meets Aluminum

While copper and aluminum can work together, they require special connectors to join these different metals. The problem begins when two dissimilar metals meet; a chemical reaction takes place that causes them to oxidize. Oxidation causes a high-resistant connection to develop with an unwanted voltage drop across the connection. Voltage drop leads to three potential problems: low voltage resulting in equipment damage, wasted energy and poor efficiency -- and the most dangerous of all -- the connection heats up and can contribute to fires at high-ampere loads.

Expansion and Contractions

Aluminum and copper do not expand and contract at the same rates as they heat up and cool down. This difference can cause wire splices or connections to work loose. A loose connection, whether at a splice in a junction box or at a terminal screw on a switch or receptacle can cause arcing. Loose connections are forerunners to arc faults, arc flash and fires in electrical systems.

Copper and Aluminum Connections

Electricians can splice copper and aluminum wires together by using special copper-aluminum connectors. You cannot splice them using a standard wire nut without dire consequences. Connectors identified with a "Cu/Al" splice contain a chemical compound that combats the oxidation that would normally take place when joining aluminum and copper. Many of these Cu/Al-splicing connectors require special tools and expert knowledge to use correctly. These connective devices require expensive tools typically beyond the reach of the average do-it-yourself person; leave them to the professionals for safe results.

Connective Devices

Modern devices when marked with Cu/Al indicate safe use with either aluminum or copper wire. But devises marked with just a “Cu” cannot be used safely with aluminum wire, as it is designated for copper use only. When a device marked “Cu” is used with aluminum wire, all the problems previously described can occur and a fire can happen at any time.

Thanks for that.

I thought so as the connector has a big Al sign on it.

I haven't put the cover on everything yet (cause I thought I would probably have to change the connector).

Just feel like another 200 km round trip drive tomorrow.

[RichCor]

Temporary/Short term use probably won't hurt anything. It's what happens over time is the concern (Cu + Al + O₂ or H₂O = potentially unwanted circumstance)

[carlyai]

Had a few wins lately.

Checked the incoming phases today and aroung: 215, 225, 219 morning and same arvo.

When I rearanged my incoming conumer unit to a DIN type, I ran my pump breaker from, you guessed it, the 215 v phase.

Good thing about 3 phase, I just swapped the pump to the 225 V phase.

Tonight no probs so far.

I have connected up the house AVRs on no load, and no problems so far.