Phase ground lamps circuit for 600V Delta system

Hi All!
Installing an outdoor construction power transformer...4160 Delta/600 Delta.
Need phase ground lamps on the 600V side.
Anyone know of a circuit diagram...specs for a simple phase loss lamp box?
Thanks
Best to All
Fred
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Delta.
I have never seen a phase ground 'LAMP" or clamp for that matter. Joslen sells a lot of clamps that are used for grounding cables. All of the transformers I have worked around have landing areas in the secondary side for the phases, neutral and a grounding bar for the grounds. 3/8 bolts, nuts, washers and lock washers with the appropriate landing lug was all that was needed.
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He is talking about lamps that tell you if you have an inadvertant ground connection on delta circuits.
Unfortunately, I don't have a handy reference for the circuit.
Charles Perry P.E.
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Yes, thanks Charles...that is what I'm looking for...just had a thought...how about 600V rated candelabra base lampholders with NE2 screw shell lamps...shell to ground and contacts on each to A,B, C??
Think I may have seen resistors in series with the lamps as well in the past....wonder what size, value of resistors would be appropriate??
Fred

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Fred wrote:

The full blown version uses relays as detectors with one relay in between the phase and ground on each leg. One contact of the relay energizes the alarm buss wire which in turn lights a light indicating the faulted phase by using another contact of the phase relay that is not pulled in because it is on the grounded phase. The alarm buss also powers an alarm sounder via a silencing relay that can be energized from the alarm buss using a momentary contact switch and holds itself closed using one of it's own contacts until power is cut off from the two pulled in alarm relays by deenergizing the circuits and clearing the fault. -- Tom H
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Well, a version of a circuit for an detection of problems in an isolated power supply (for an operating room) might be appropriate. (I saw this in a NEC handbook of a few years (decades?) back.
Basically, with you take your "floating" delta source and "center ground" it via a "Y" resistance network. The value of the resistance in each leg will be a function of the desired sensitivity, maximum leakage during a ground fault and such.
A second "Y" resistor network is also connected to the delta supply. The center of this "Y" is your "sensing" point. A voltage detector is connected between ground (and the first "Y" center) and the center of the second "Y".
If there is no leakage, everything is balanced and your voltage detector see zero volts. If the delta source suffers unsymetrical leakage, a voltage will appear between ground the center of the second "Y".
The voltage sensor can trigger an alarm or whatever. The sensor could be a relay coil. The relay can be made to latch up by having an extra set of contacts transfer the grounded side of the coil to one of the phases of the delta.

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HorneTD wrote:

The simple ones consist of two lamps in series per phase, grounded in between the two lamps, and a fuse at each phase lead. Each lamp is rated at phase voltage so they all (6) burn very dim until one phase is grounded. Then the two lamps closest to the grounded phase leg go out, and the remaining lamp in each phase closest to the grounded leg burns at normal brightness.
I haven't seen any lately, but of the two types I've seen in the past I preferred one where lamp modules were used that contained a transformer with a low voltage lamp. I can't feature the design with full voltage lamps at 600v being available anymore let alone acceptable to any AHJ!
Louis
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| Installing an outdoor construction power transformer...4160 Delta/600 Delta. | | Need phase ground lamps on the 600V side.
My non-engineering guess:
Get 4 347-volt bulbs. Wire 3 of them in a WYE arrangement to the three phase lines. Wire the 4th bulb between the star point and ground. Label the first three A and B and C. Label the 4th as G. You should see dim light in A and B and C, and no light in G, in the normal case. In the case of one phase faulting to ground, you should see them deviate towards no light in the faulted phase, and light in G, varying depending on the degree of fault impedance.
This setup is subject to false negatives. If bulb G has burned out, it won't show a fault. Multiple bulbs in parallel helps reduce the risk, but 347-volt bulbs are not cheap, and do poorly at low wattage. These would need to be incandescent bulbs.
Three test switches that connect a heavy duty impedance to ground (be sure to choose values that won't cause a problem if 2 or 3 switches are closed at the same time) can be used to verify if the bulbs are working.
| Anyone know of a circuit diagram...specs for a simple phase loss lamp box?
Loss of phase on the primary would give you mixed voltages at single phase on the secondary. If phase B goes out, you would see 300 volts on A-B and B-C. The simple circuit would be 3 600 volt bulbs in delta, and watch for 2 of them going very dim; their common phase being the lost one.
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snip

snip
Off subject:
Could you point out some website discussing 347V incandescent. I never called for incandescent in 347V because I understood it was not available. I don't know why it would be so hard to achieve.
j
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| | snip |> but 347-volt bulbs are not cheap, and do poorly at low wattage. These |> would need to be incandescent bulbs. |> | snip | | Off subject: | | Could you point out some website discussing 347V incandescent. I never | called for incandescent in 347V because I understood it was not available. | I don't know why it would be so hard to achieve.
I've seen them for sale on an online web site somewhere. They had a wide selection of voltages up to 347. ISTR that 347 only came in 100 watts, while 277 came in several wattages.
Higher voltages need longer filaments and are only practical in higher wattages. At low wattages they would distribute the power over more filament surface, and run at a lower color temperature. Not good efficacy, but for circuit monitoring purpose, probably not an issue.
So put a 45 watt 1800 ohm resistor in series with a 15 watt 120 volt light bulb.
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From: snipped-for-privacy@ipal.net
| snip but 347-volt bulbs are not cheap, and do poorly at low wattage. These would need to be incandescent bulbs. | snip | | Off subject: | | Could you point out some website discussing 347V incandescent. I never | called for incandescent in 347V because I understood it was not available. | I don't know why it would be so hard to achieve. I've seen them for sale on an online web site somewhere. They had a wide selection of voltages up to 347. ISTR that 347 only came in 100 watts, while 277 came in several wattages. Higher voltages need longer filaments and are only practical in higher wattages. At low wattages they would distribute the power over more filament surface, and run at a lower color temperature. Not good efficacy, but for circuit monitoring purpose, probably not an issue. So put a 45 watt 1800 ohm resistor in series with a 15 watt 120 volt light bulb. -- ---------------------------------------------- Phil you're a Wizard };-) When are you Planning your trip to NYC?
Note: forget that agancy that turnt down your bid and hit the winner up for some of the work with a same fee, (they allow to farm out some of the work don't they all?) subcontract with less red tape, if he says no I'll look into it myself & you won't be alone....did you cover all the angles = Insurance, licences, plans, permits etc. I am aware some real shitheads are left in control at times, they can't get too far.
oy
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wrote:

Delta.
box?
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> | Phil Howard KA9WGN | http://linuxhomepage.com /
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I see what you are saying. There being 2 lamps (C and G) in parallel between phase C and the star point (I guess that's what you are labelling N), that star point is pulled closer to C, raising the voltages to lamps A and B on their respective phases.
So 347 volt lamps, could be risky there ... as risk as running 120 volt lamps on 127 volts.

It was avoiding the 600 volt case that I put lamp G between the star point and EGC/earth.

I was thinking in terms of the need to have 2 347 volt lamps (or 277+347) in series for the solidly grounded star point as being 6 lamps, not expecting to find 600 volt ones. I was trying to save 2 lamps.

Now that I think about it as you describe, it's obvious lamps A and B get more voltage than the normal L-N voltage when a solid ground fault on C lets C and G work together to pull the star point over towards C.
I don't think I would want to put multiple 120 volt lamps in series as one could get substantial voltage across a burned out filament. So maybe the way to go is three big resistors and 3 120 volt lamps (A,B,C), or three 600->120 volt transformers and the same lamps.
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wrote:

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---------- I have to agree with you on that- however use of a smaller wattage resistor and a neon might work well. The lamp approach was one that was used with early systems (120 or 240V) which were generally delta. It may be that more sophistication might actually be more economical and reliable.
--
Don Kelly
snipped-for-privacy@peeshaw.ca
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|> I don't think I would want to put multiple 120 volt lamps in series as one |> could get substantial voltage across a burned out filament. So maybe the |> way to go is three big resistors and 3 120 volt lamps (A,B,C), or three |> 600->120 volt transformers and the same lamps. | ---------- | I have to agree with you on that- however use of a smaller wattage resistor | and a neon might work well.
I'm sure that will work well.
| The lamp approach was one that was used with early systems (120 or 240V) | which were generally delta. It may be that more sophistication might | actually be more economical and reliable.
I wonder why delta is still popular, as opposed to getting the same from a wye, e.g. 600Y/347 instead of 600D, or 480Y/277 instead of 480D. For 240 delta with a 120 volt tap, that I can understand as a cheaper way to mix 120 volt lights and three phase power at correct voltage (going wye means either under power three phase loads at 208 volts, or get 240Y/139 which can't be used on lighting at all).
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I see ungrounded deltas in old industrial buildings in Chicago. These systems were installed in the 40's and 50's. Typically 12kV into the vault, feeding a 480 delta transformer. The original facilities had heavy three-phase loads, so there was no attempt to add the lighting loads to the same transformer. They installed a second transformer for 240/120 single-phase loads.
Today, many of these buildings are being converted to multi-use commercial application, where most of the loads are single-phase. They either add 480-240/120 single-phase transformers feeding various panels, or replace the service with 208/120. In the latter case, the few three-phase loads, such as elevators or a/c, run on the 208 with no problems.
Ben Miller -- Benjamin D. Miller, PE B. MILLER ENGINEERING www.bmillerengineering.com
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| Today, many of these buildings are being converted to multi-use commercial | application, where most of the loads are single-phase. They either add | 480-240/120 single-phase transformers feeding various panels, or replace the | service with 208/120. In the latter case, the few three-phase loads, such as | elevators or a/c, run on the 208 with no problems.
I hope they are using motors rated for 208 volts. I've been involved in a couple cases of motors burning out because they were getting 208 volts and were not rated for it. But given that 208Y/120 is common, I would think lots of motors, especially three phase models, would be available for the voltage. The cases I was involved with were single phase motors.
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snipped-for-privacy@ipal.net writes:

I think in many cases it is for industrial use where if power is removed, something bad happens, such as molten glass solidifying in equipment, ruining it. They run ungrounded delta so the system can tolerate one ground fault, if the fault happens, they can shut down the system properly and find/repair the fault. With a grounded wye or a grounded (anywhere) delta, the single fault will trip a breaker/blow a fuse and something will shut down unexpectedly.
--
-Mike

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<snip>

In the Navy, we had 120V-delta connected three-phase 'lighting' transformers supplying lights and misc 120V loads. To test for grounds, we had three 12V lights in series with 3 resistors, tied in a star formation. The center of the star was connected to a momentary, normally open push-button whose other side was ground.
As auxilary electrician, for a couple of patrols, I had to push that button every hour on watch and note whether the brightness of the lights changed. If there was a significant change, I had to log it and report a ground on the system and we'd have to perform 'ground isolating' to find it. Once, the ground turned out to be one of the transformer secondarys and we had to re-wire it open-delta, the loss in capacity meant we ran with many lights off (the 'mood lighting' was the subject of many jokes that patrol).
Ah, those were the days.... (NOT!!!)
daestrom
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why mess around with 600 volt it really makes a mess when things go bad Square D GFI Panel is what is used around here only use approved equipment on this voltage

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