Intemittent power (loosing a leg) and delay on break for condenser

[Robert Adams]

Ok we have very unreliable power here not to mention lots of noise and other dirty power issues here. The elec company doesn't do much other than repairs when it goes down which they are quick about it because every minute the power is down in the summer that's cash not coming in....

      The main issue is that they have a consistent problem where one leg tends to go out intermittently for a split seccond. It's been going on for 10 years and its the entire neighborhood. Often I will hear some of my ups kick in because the power gets too dirty and they kick in. That leg still has power but not consistent. Then at times the UPS will beep kick in then I can hear a fuse on one of the transformers go. There are two in the neighborhood that are the usual culprits... I think their main issue here is the very old system here can't take the load of modern houses. 
      Our feed for the house is a 200' run from the house to the pole that has single phase on it the transformer is way down the street... Not to mention undersized conductors (Im a commercial electrician)as they don't care how hot their wires get nor the voltage drop on them...


         So the issue with the AC is that one leg will drop out just long enough while the condenser is on and the compressor will turn backwards. I have a delay on break timer on it but that only gets triggered if the power from the air handler gets disrupted. Well if the phase that goes down isn't the one that powers the air handler then it thinks everything is SOP. (air handler is 110v)

         So what i am looking for is some sort of delay on break that is triggered by the condenser power feed not relying on the thermostat feed dropping out. They have been having lots of issues today and the condenser has spun backwards 3 times today. Luckily while I was at home and I could turn the AC off. I am going to move the air handler feed to the other leg as it seems it is not on the one with the most issues so the relay would be more likely to be triggered.... 

        Oh and 2 neighbors that were out have the same issue and I know for a fact one has a delay installed.

[Roly]

Ok we have very unreliable power here not to mention lots of noise and other dirty power issues here. The elec company doesn't do much other than repairs when it goes down which they are quick about it because every minute the power is down in the summer that's cash not coming in....

      The main issue is that they have a consistent problem where one leg tends to go out intermittently for a split seccond. It's been going on for 10 years and its the entire neighborhood. Often I will hear some of my ups kick in because the power gets too dirty and they kick in. That leg still has power but not consistent. Then at times the UPS will beep kick in then I can hear a fuse on one of the transformers go. There are two in the neighborhood that are the usual culprits... I think their main issue here is the very old system here can't take the load of modern houses. 
      Our feed for the house is a 200' run from the house to the pole that has single phase on it the transformer is way down the street... Not to mention undersized conductors (Im a commercial electrician)as they don't care how hot their wires get nor the voltage drop on them...


         So the issue with the AC is that one leg will drop out just long enough while the condenser is on and the compressor will turn backwards. I have a delay on break timer on it but that only gets triggered if the power from the air handler gets disrupted. Well if the phase that goes down isn't the one that powers the air handler then it thinks everything is SOP. (air handler is 110v)

         So what i am looking for is some sort of delay on break that is triggered by the condenser power feed not relying on the thermostat feed dropping out. They have been having lots of issues today and the condenser has spun backwards 3 times today. Luckily while I was at home and I could turn the AC off. I am going to move the air handler feed to the other leg as it seems it is not on the one with the most issues so the relay would be more likely to be triggered.... 

        Oh and 2 neighbors that were out have the same issue and I know for a fact one has a delay installed.

Swap the feed to your furnace to the other leg in the panel.   Roly

[blackhat]

Install a 240/24 v transformer on the line side of the condensing unit contactor . 
Run the transformer output through a delay on make timer and to the coil of a small relay. Use the contacts of that relay to make/break the control voltage to the condensing unit. Won't help for low voltage on a leg depending how low it goes but would give you a break on complete loss of a leg. I can ask around next week about power monitoring modules, some new equipment is factory fitted with them.

[daddo]

I have installed a second contactor with a 240v coil that must receive 240v or it will open the 24v when run through it's contacts. This protects from voltage loss from either leg. A 24v TD relay (make or break) is installed after the contacts.
Check that one common leg isn't hot to the motors all the time- there might not be enough resistance to drop the secondary contactor.

[pprobus]

Ok we have very unreliable power here not to mention lots of noise and other dirty power issues here. The elec company doesn't do much other than repairs when it goes down which they are quick about it because every minute the power is down in the summer that's cash not coming in....

      The main issue is that they have a consistent problem where one leg tends to go out intermittently for a split seccond. It's been going on for 10 years and its the entire neighborhood. Often I will hear some of my ups kick in because the power gets too dirty and they kick in. That leg still has power but not consistent. Then at times the UPS will beep kick in then I can hear a fuse on one of the transformers go. There are two in the neighborhood that are the usual culprits... I think their main issue here is the very old system here can't take the load of modern houses. 
      Our feed for the house is a 200' run from the house to the pole that has single phase on it the transformer is way down the street... Not to mention undersized conductors (Im a commercial electrician)as they don't care how hot their wires get nor the voltage drop on them...


         So the issue with the AC is that one leg will drop out just long enough while the condenser is on and the compressor will turn backwards. I have a delay on break timer on it but that only gets triggered if the power from the air handler gets disrupted. Well if the phase that goes down isn't the one that powers the air handler then it thinks everything is SOP. (air handler is 110v)

         So what i am looking for is some sort of delay on break that is triggered by the condenser power feed not relying on the thermostat feed dropping out. They have been having lots of issues today and the condenser has spun backwards 3 times today. Luckily while I was at home and I could turn the AC off. I am going to move the air handler feed to the other leg as it seems it is not on the one with the most issues so the relay would be more likely to be triggered.... 

        Oh and 2 neighbors that were out have the same issue and I know for a fact one has a delay installed.

Are you sure its the "whole neighborhood"?  I had a similar problem about a year after we moved in and it turned out to be a loose lug/wire in the meter.  After about a year of intermittently losing a leg, it finally burned out enough to lose the leg completely and the power company replaced the meter.  It was quite maddening as 1/2 the house would have power and the other half would not, definitely not something I would have put up with for 10 years.

[Robert Adams]

Are you sure its the "whole neighborhood"?  I had a similar problem about a year after we moved in and it turned out to be a loose lug/wire in the meter.  After about a year of intermittently losing a leg, it finally burned out enough to lose the leg completely and the power company replaced the meter.  It was quite maddening as 1/2 the house would have power and the other half would not, definitely not something I would have put up with for 10 years.

 
          Yup it's everyone. Both sides across the street... and usually when it hits the fuse will blow on one of 2 transformers. The UPSes start kicking in when they sense a voltage drop then you will hear the whump of the fuse blowing(when it's enough to blow it)  The power poles here were put in around the 40s and most of that is all original. Very few transformers most of the houses are run off of the low voltage lines on the poles so like us we have around 200' of wire running from the meter to the pole then it's another 1k' to the closest transformer.

[Duane N]

Touching on what blackhat suggest about phase monitoring...how about something like this?

https://www.icmcontrols.com/productdetails/ICM491

Single-phase line voltage monitor with ASC protection; protects against hi/lo voltage and rapid system recycling; 95-270 VAC

Details:
* Low cost single phase motor protection * Built in anti-short cycle protection * Detects high/low voltage conditions * Helps prevent rapid short cycling * LED indicators: -Green for normal conditions -Red for fault * Heavy duty SPDT, isolated relay output
Weight/Dimensions:

• Weight: 0.35
  
• Height: 1.25
  
• Width: 3
  
• Length: 3.25
  

Specifications:
Voltage: 95-270 VAC

Output:
- Relay, SPDT
- N.C./N.O.: 5 amps
 
Time Delay Range: Adjustable 6-600 seconds

[blackhat]

That would work.  You would have to switch 24 with it, the contacts aren't rated heavy enough for full unit current.  That's pretty easy.

[Robert Adams]

That would work.  You would have to switch 24 with it, the contacts aren't rated heavy enough for full unit current.  That's pretty easy.

    Yup I like that. Same company that makes the timers as well. Will get one on the way. Easier than the other method with the relays which I did dig one out after reading your prior reply... 

      Was busy this weekend running pipe and wiring a 40x40 shop by myself. It was 95* before noon there and it is a metal building with no insulation. So 120+ inside easily. Miserable weekend of heat exhaustion and still have to go back and install the lights (without a scissor lift). Have I ever mentioned I hate living here.... Just too hot.

Oh how I wish I could get 3 phase for the house and shop... I would love to run three phase condensers a mill a lathe etc. I am working on my metalworking tools (toys).