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PA BEN
03-16-2007, 08:51 PM
Brian you’re the on call lineman. You get called out at 1 am to the only grocery store in town. Part power is the call. You call your pole partner to meet you. When you arrive at the Safeway store you see that the lights are on. The manager tells you his motor savers on his compressors are open because of single phasing. He says he’s going to lose all his food, and being the only store in town he needs to open at 7:00am if all possible. The store is fed by a Y Y 120/208 bank on a platform in the back of the store. The platform bank is fed by a under ground riser into cutouts on an arm above the bank. The riser tap is a block away. One cutout on the tap is open but none on the Y Y bank. This is old 175 mil open concentric cable direct bared. Across the street and down ˝ a block is an alley with a single phase line deadened on a transformer pole. The single phase line is taped off the same feeder as the Y Y Bank. With this info what do you do?

P.S. No dead animal at the base of riser pole!!!

dbrown20
03-16-2007, 09:22 PM
Phone rings. 500 answers. "What?" Brian. "500, 500, 500, the safeway store is single phasing. What do I do?" "Helps me, helps me."

500. "You little puke, you make me want to throw up." Click.

500 KVA
03-18-2007, 12:05 AM
You must have been listening on our party line when he called.

Brian if you need me I'll come out with you but I always like an eye opener first. Give me about 20 minutes.

Hemingray Insulators
03-18-2007, 01:11 PM
First retry with a new fuse :eek:

if that dont work then
i reconfigure the bank to a open delta on the high side................I THINK :confused:

topgroove
03-18-2007, 03:29 PM
sometimes your gonna have to run temporary overhead in your career. After you trouble shoot and and find a fault in the underground URD, and isolate it, you have to deside ... is it better to re-wire the bank or run temporary overhead keeping the customer hot while you repair the underground.in this case you could probebly only run one phase of #6 cu a half a block to pick the customer up. Open delta is a good choice but you reduce your KVA by about 33% sometims you can overload the customers mains if there load is too high... just something to think about.

dbrown20
03-18-2007, 04:42 PM
First retry with a new fuse :eek:

if that dont work then
i reconfigure the bank to a open delta on the high side................I THINK :confused:

Actually there is a way to get 3 phase 208 with a source of 2 primaries and a neutral. Would you describe it to me Brian? I really don't think you know how to do it. Making an open delta out of a Wye/Wye bank is somewhat nefarious also. dbrown20

PA BEN
03-18-2007, 05:47 PM
Good one Brian. You would test the cable first. If you have a Hi pot tester that would be the best way. But trying a fuse works too. A shoe fly like topgrove said would be the fastes way to geter done.:D I've never herd of a 208 open delta I'd like to see how one works.

Hemingray Insulators
03-18-2007, 09:27 PM
Actually there is a way to get 3 phase 208 with a source of 2 primaries and a neutral. Would you describe it to me Brian? I really don't think you know how to do it. Making an open delta out of a Wye/Wye bank is somewhat nefarious also. dbrown20

your right, i don't know how to wire it up for sure, but i was tryin to remeber what you called it, last time there was a discussion on getting 3 phase from 2 phases and neut. im thinkin it was phase in H1 on one pot, and H2 on other pot, with H2-H1 in between conectd to neutral.........can't remeber if thats how its done or not...................

grillman
03-18-2007, 10:07 PM
I have never heard of getting 208 from a delta. Only Wye. We only have 240 and 480 deltas. I would like to know more about this, though, if you could get 208 from a delta. I always heard you had to cut over your pots, and have all grounds in place to achieve 208 volts. On a delta though you can only have one gorund, is what we were always told. Anyone ever hear different.

topgroove
03-19-2007, 06:56 AM
so running tempory overhead would have been the best choice right brian...

Hemingray Insulators
03-19-2007, 11:45 AM
so running tempory overhead would have been the best choice right brian...

Well assuming that you don't have too many poles to set to run temp. OH and there are not many trees in the way, then i'd say it'd be the way to go. i wanna hear from Dbrown how you wire up the bank from 2 phases and a neut.

topgroove
03-19-2007, 12:45 PM
half a block away was the tap pole straight down the ally. no need to set any poles and if you have to run through a tree well that's what rubber hose is for.I think that's what pa was hinting at brian. I too would intrested in learning how to get 3 phase 208 out of a 2 pot bank. i've never run across it myself. sometimes loading is a issue expecially when your talking about a super market.lots of heavy -load compresors and refrigeration equipment. you start burning up customer equipment and you wipe out a lot of attaboys.

dbrown20
03-19-2007, 01:42 PM
I've described this setup several years ago. I would have to dig out paperwork to make sure of the load sizing etc. but here is the hookup. It is not 3 phase 208 from a 2 pot bank however, it is 3 phase 208 from a source with 2 phases and the neutral in a Wye system.

Again I'm not sure how much load it will carry. I'll look it up sometime.

Consider 3 transformers setting with the secondary facing you on a platform. The 2 on the left have their coils paralleled and the one on the right is left as is. They of course all have 120/240 volt secondaries. The 2 on the left are cut to the right as the book shows for additives. The X3 of the pot on the right is connected to the far left secondary bushing of the pot in the middle. The far right bushing of the middle pot becomes one hot phase of secondary. The far left pot is left by itself and it's right hand bushing is grounded to the system neutral. It's left hand bushing becomes another phase of secondary. The X1 of the conventional pot becomes another phase of secondary with the X2 of course being connected to the system neutral. The 2 pots with their coils paralleled are hooked to the same primary phase. There you have it. This may not be right, I'll look at a drawing sometime but I think it's correct. This actually can be done with 2 pots if one has external secondary bushings like a 167 KVA or larger. I'll bet you could get 120/240 single phase out of this also.

I have actually seen this in operation at a turnpike tollgate. Just glancing at it while driving by it looks like probably a 50 KVA and two 25's. Maybe. If you have one of those little mock transformer setups, give it a try. dbrown20

PA BEN
03-19-2007, 09:24 PM
The veterinary clinic calls says the lights flicker and the battery back ups on there computers beep because of low voltage. Doesn’t happen all the time but it’s getting old. Your on the service truck with 500 that day as an apprentice, 500 says, “well kid figure it out”. A 37.5 KVA feeds open wire secondary witch feeds the clinic and two house’s across the street. What do you check? And what do you look for? I'll add more after your answers.:D

P.S. This is some old stuff.

Hemingray Insulators
03-21-2007, 11:48 AM
First i would check under load voltage, and measure amps on the pot leads to see if the transformer is overloaded. next i would check the vets connections. i look for loose or burnt connectors.

BigClive
03-21-2007, 06:17 PM
sometimes loading is a issue expecially when your talking about a super market.lots of heavy -load compresors and refrigeration equipment. you start burning up customer equipment and you wipe out a lot of attaboys.

And since the fridges and freezers have been off for a while and their temperature has risen, all those big compressors are going to kick in at once and put the worst possible load on your fix.

BigClive
03-21-2007, 06:42 PM
The veterinary clinic calls says the lights flicker and the battery back ups on there computers beep because of low voltage. Doesn’t happen all the time but it’s getting old. Your on the service truck with 500 that day as an apprentice, 500 says, “well kid figure it out”. A 37.5 KVA feeds open wire secondary witch feeds the clinic and two house’s across the street. What do you check? And what do you look for? I'll add more after your answers.:D

P.S. This is some old stuff.

Well I decided to check over at the houses to see if they had experienced the power fluctuations too. As I approached the first house there was a loud bang and blue flash from inside and all the lights dipped. I anxiously rang the doorbell and it was immediately opened by a middle aged man wearing a pair of cheap Sears coveralls with a huge coppery skid mark up the front. "Can I help you?" he said in a shaky voice, and as he removed his glasses I noticed that his face was all sooty except for two pink circles where his spectacles had been, his eyebrows also seemed to be missing and his hair was swept back in an unusual manner. Looking down at the floor I saw the charred remains of a book called "rewiring for beginners" and noticed that the pair of good quality pliers in his left hand had a huge hole where the cutting edges had been.

"Umm, I was wondering if you had umm noticed any fluctuations in your electric power." I said firmly.

I could tell he was scared from the way the corners of his mouth twitched downwards. "No.. No.. Nothing at all." He whimpered.

"He's been doin' something weird!" Came a shrill female voice from the other house. "It's just been flashes and bangs all day and my lights keep dipping. I don't know what he's up to."

"You grassing BITCH!" screamed the man before bursting into tears and slamming the door shut.

"Sir! Do you mind if I come in and check your electrical supply." I shouted through the letter box. "No F*CK OFF! Go away and leave me alone" he whimpered. "Go away or I'm calling the police."

I went back over to the vets and explained that their neighbour was attempting to rewire his house without turning the power off first, and that they might experience a few more brown-outs until he blew his supply completely.

Job done.

PA BEN
03-21-2007, 10:14 PM
First i would check under load voltage, and measure amps on the pot leads to see if the transformer is overloaded. next i would check the vets connections. i look for loose or burnt connectors.
BC that was good, But that wasn't the problem:D Hem. BC is right check the houses to see if they have the problem too. In this case they don't. So you've done the above checks. The old split bolt connectors have tap on them. And the tap isn't burnt and the wire doesn't look like it hasn't been getting hot. What do you do next?:D

PA BEN
03-24-2007, 12:15 PM
Remember 500 said this is your job. So you go in and talk to the owner of the clinic to arrange an outage to check the meter base, put the beast of burden on it you know the drill, but the owner said the only time is in 5 mins and you can have it off for 20 mins or Sunday all day when there closed. You remember 500 talking about the new fish finder he wants to get for his boat and you love O.T. at double time. So you say to 500, “The man said Sunday is the only time it will work.” The O.T. won’t hurt will it? “Kid I love the way you think”!! Sunday it is, but what are we going to do? :D

dbrown20
03-24-2007, 01:09 PM
Changed out a leaker once on a OH 208 bank. Served a restaurant. Went inside and determined the only 3 phase they had was a dish washer. Told them if alright, we would blink some of their lights and the dish washer would be down for awhile. They said okay. We put a load pickup jumper on the leg from the bad pot to a leg on a good pot. Opened the bad pot and popped the load pickup. Took down leaking pot and replaced it. Did reverse procedure and everything okay.

Had another 208 leaker in an OH bank. A span away was a conventional 120/240 pot. Put a piece of triplex to this pot from the OH bank. Paralleled the 208 pot with one side of the conventional. Changed the leaker and put it all back together the same way taken apart. No outage at all.

Had a single phasing condition called in at a Chinese restaurant. They had a 208 padmount that had one elbow burned up along with the transformer bushing on a dead front. The transformer would obviously have to be changed. Went into the restaurant and the only 3 phase was the air condtioning and the blower in the kitchen that sucked out the smoke etc. from the stoves. It was their busy time and the restaurant was packed. Told them we could keep everything on until the customers were cleared out and that they would have no air and the blower wouldn't work. They said fine. Put the load pickup from the dead leg to a live leg. Cleared up the bushing etc. and closed the load pickup. After changing the pot and getting things back to normal they gave us a free lunch. Okay if you like Chinese food.

Buried some URD into a 208 padmount once. It served a fire station and had a single phase 120 volt that went to a nearby traffic light. I can't remember the reason but anyway rerouting the URD. When the new elbows etc. were made up I looked at the schematic and could tell which primary served the 120 volt service. Our supervisor made a big deal of the change over. He arranged for a cop to be there to direct traffic etc. while the light was off. I tried to tell him that it would only be a blink but he got smart with me and reminded me he was the boss and would call the shots. I said okay. I talked to the lineman who was opening the old dip and closing in the new and I said when I give you the high sign you close a particular dip first after I get the elbow plugged on for the single phase. Everything was arranged and the guy was up in the bucket and the cop showed up on his motorcycle and set up in the intersection and gave us the okay to kill the light. I waved at the lineman and he opened all three old cutouts and I immediately plugged in the new elbow on the single phase. The signal light hardly blinked and the cop looked over at us and I said Okay we got it. He had a puzzled look and left on his motorcycle. Our boss had told the cop it would be about a 5 minute outage and it was about 10 seconds. He said. Well I guess that didn't take very long. I replied. Tried to tell you. dbrown20

Orgnizdlbr
03-24-2007, 01:40 PM
Changed out a leaker once on a OH 208 bank. Served a restaurant. Went inside and determined the only 3 phase they had was a dish washer. Told them if alright, we would blink some of their lights and the dish washer would be down for awhile. They said okay. We put a load pickup jumper on the leg from the bad pot to a leg on a good pot. Opened the bad pot and popped the load pickup. Took down leaking pot and replaced it. Did reverse procedure and everything okay.

Had another 208 leaker in an OH bank. A span away was a conventional 120/240 pot. Put a piece of triplex to this pot from the OH bank. Paralleled the 208 pot with one side of the conventional. Changed the leaker and put it all back together the same way taken apart. No outage at all.

Had a single phasing condition called in at a Chinese restaurant. They had a 208 padmount that had one elbow burned up along with the transformer bushing on a dead front. The transformer would obviously have to be changed. Went into the restaurant and the only 3 phase was the air condtioning and the blower in the kitchen that sucked out the smoke etc. from the stoves. It was their busy time and the restaurant was packed. Told them we could keep everything on until the customers were cleared out and that they would have no air and the blower wouldn't work. They said fine. Put the load pickup from the dead leg to a live leg. Cleared up the bushing etc. and closed the load pickup. After changing the pot and getting things back to normal they gave us a free lunch. Okay if you like Chinese food. dbrown20

Were there any cats around the joint when ya were working on the place??

dbrown20
03-24-2007, 02:12 PM
they had some in a cage in the kitchen. Said they were their pets. I thought it was sort of a funny place to keep their pets. I just thought, well different cultures have different ways. The meat in our free meal was kinda stringy though. You don't think? I wondered for awhile why I didn't like dogs. Dammit. Wish you hadn't mentioned that. dbrown20