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Discussion in 'Lighting and Electrics' started by ship, Mar 25, 2009.
what's the Pilot Contact on a 63a/6H 415V 5-pin 3P+N+E plug for?
Such as on a CeeNorm #2189.
I don't see a pilot in that description--it's 5 poles only--3P-N-E.
What am I missing?
Walther Electric: IEC 309-1 & 309-2 Pin & Sleeve Devices: Design and Manufacturing .) Normally Walther shipps me CeeNorm and the part numbers didn't match up in this case of the first Walther brand plug I got.
The part number I posted was only a reference number into type/pinology, but there was a note in that CeeNorm catalog on this above plug (thanx for the photo) about this sixth pin in not connecting it up to a line load.
Chris recently emailed me the following:
I wasn’t sure if you had intended the ceeform question to be one in QotD style whereby those that know should hold back on answering or not...
As best I understand it, the pilot contact is used is some setups to interlock the connection electrically so that when the pilot engages, the power turns on via contactor and the reverse on removal. Helps overcome arcing issues and other such badness.
Hope that helps...
I asked him to post further info.
phase, whereby they have an idiot check built in. The system will not energise until the pilot pin has made contact. The pilot pin will be shorter and thinner than the load pins. It makes last and breaks first and so when you lose it, the contactor drops out before the live pins are far enough out to arc. Because Ceeform has the socket flap hook the plug in when plugged, the likelihood of the plug falling otu accidentally is minimal, so you don't get much nuisance disconnection.
I'll have to admit that I've never actually used such a system. I do know we have the extra pins in our 56 series connectors as an option and I have read I think it was military specs where their system (in this case a 400 Hz supply for an aircraft I think) would energise upon the plug being properly engaged and deenergise as the plug came out.
I should think it possible to use it effectively as a switch to probably Neutral in a 240 etc control circuit, noting that not using ELV gets around some electrical rules in bits of the world and also gives the benefit of a slight amount of cleaning from the ozone created from the tiny arc at connection and disconnection.
From memory, sockets will take piloted or unpiloted plugs. I seem to remember when last I were in the office us having some plugs with pilots lying around, so obviously we've had no issues. They would have been the Mennekes equivalent of that 63A 5 pin red. (Don't know if you've tried those ship, but I've found them resonably good and not too hard to wire either - some plugs have WIERD strain reliefs that are a pain to work with).
At any rate, I would think you could pull the pin out. Unless you had a really wierd venue, I doubt they would have the interlock enabled and I would have to think that there was multiple ways of wiring them, all of which could create a bang if bits from dissimilar systems were used together. Perhaps send the pins with the Euro boys in case they need them. Else have a look at the next 63 red C you see and see if the hole is there to just leave em. I expect to me in the office next week and assuming I remember, could check the sockets then.
Probably now at the point of specific questions being easiest rather than trying to guess what people don't know...
ground in both nonmining and mining applications. US NEC only requires this for 1,000-volt and greater cords for mobile equipment.
Since I have helped set up the annual automotive show at International Exposition Center in Cleveland, Ohio and know that a booth can easily use 1/4 or even 1/2 a megawatt of power, I figure that you have uses for 120-volt, 480-volt, 4,160-volt, and 13,800-volt extension cords.
Theoretically, in a mine in the US you can walk up to a 4,160 volt branch circuit cord and use a small hammer to tap a nail into it and all you should get is a small puff of smoke. Coal mines in England have had ZERO electrocution deaths since 1963 and they have 1,100 volt and 3,300 volt extension cords so they must be doing something right.
The ground monitor relay of the half rectifying type that uses a terminating diode to connect the ground check wire to the frame of a mobile machine is very popular. This is because a switch or start-stop buttons between the ground check wire and the terminating diode can be used to remotely deenergize and reenergize the power source of the cord. Another type of relay uses a terminating resistor but must be calibrated for the particular ground check-equipment ground loop. The ground monitor relay needs some type of terminating device to distinguish a good ground check wire from one that is ground faulted or power crossed. In the case of the half wave rectifying circuit if the relay sees anyting other than the proper polarity of half wave rectified AC the relays trips on the basis that the ground check wire is ground faulted, power crossed ( including direct current ), or the terminating diode is installed backwards.
In the case of impedance type ground monitor relays a decrease of resistance indicates a ground fault or power crossed ground check wire which is bypassing the terminating resistor and an increase of resistance indicates a potentially open equipment ground. Impedance relays are usually designed to trip at +- 1 Ohm or +- 4.5 Ohms from the calibrated value of the ground check-equipment ground loop. Therefore, impedance relays can really be used only for a cord of fixed length.
Information on ground monitor relays can be obtained from www.smcelectrical.com , www.littelfuse.com , and www.bender.org . The SMC model C54-004 and C54-005 ground monitors are half wave rectifying and use a current transformer in series with the cord ground to distinguish a true equipment ground from a false parallel path.
Information on G-GC, SHD-GC, and MP-GC cords can be found at www.generalcable.com and then click on mining cables.
Cords that are used in dry locations at 2,000 volts or less are allowed to be unshielded and to use solidly grounded systems eg. 120/240 volts or 277Y480 volts.
120 volt to 24,000 volt AC cords in wet locations use several protection elements together. They are resistance grounding of any power sourcegreater than 16 volts AC, shielding of cords conductors over 16 volts, continuous monitoring of the equipment ground, both branch circuit and feeder equipment ground fault protection. This system provides full people protection even if the ground fault relay is set as high as 15 amps in the case of a main power feeder.
There is an out of print book titled Collier Electrician published by the British National Coal Board on how protection of high energy electrical cords works. What British National Coal Board and their American ( Mine Safety and Health Administration ) and German couterparts found was that what was causing a lot of fires and essentially all electrocutions in mines was that as a cord was flexed one or more wire strands would break and start working their way through the insulation. If the strand worked its way through to the other side a short circuit or smoldering arcing fault would occur. If the wire strand worked its way to the surface and electrocution would occur, usually when somebody stepped into current flow into moisture along the floor.
What conductor shielding and automatic continuous monitoring of the equipment ground does is to assure that a stray wire strand turns into a ground fault and electricity leaks from the cord. What resistance grounding does is to keep ground faults from burning themselves clear or turning into a smoldering arcing fault. Resistance grounding also gives protective ground fault relays time to respond to the fault and disconnect power and also when the power is off the electricians can find and remove the fault. Ground fault protection at both the branch circuit and feeder level is supposed to trip on branch circuit faults so that 2 relays and 2 circuit breakers are disconnecting the fault - this guarantees redundancy in the protection system.
There is a scenario where there can be a catastrophic bolted fault such as when a machine accidentally runs over a power cord ( about once every 10 years in the U.K. ) . This approximately corresponds to how you can choke to death on your breakfast food.
Ground fault relays need time to disconnect ground fault both because of the time that it takes to sense the fault and for a circuit breaker to trip and because there has to be an INTENTIONAL delay to allow motors to start and stop. Resistance grounding provides this time by absorbing potentional arc flash energy and by limint the fault to a relatively low level of current compared to a bolted or arcing fault.
When a motor starts there is an initial phantom "ground fault" because of charging of the winding insulation capacitance to ground. When the starting switch of a single phase motor opens and when all motors are turned off ( both single and three phase ) winding inductance forces a phantom "ground fault" to flow through winding insulation capacitance to ground what is known as a second order transient ground fault.
For a 120 volt ground fault circuit interrupter receptacle or circuit breaker the intentional time time delay needs to be a minimum of 1/10th of a second. Underwriters Laboratories allows a maximum inverse time delay of
Ground fault current maximum time delay
6 milliamperes 5.59 seconds
10 mA 2.69 sec
20 mA 1 sec
30 mA 0.56 sec
In a wet location such a as a bathroom this is acceptable because hair dryers normally do not get wet. In a waste water treatment room of a factory this is unacceptable and would wrap somebody's arm around their head. This is because electronic devices and so forth are going to have some amount of moisture inside that would leak some amount of 120 volts back through the equipment ground.
What automatic continuous monitoring of the equipment ground does is to say that it is the equipment ground that protects people against shocks so shut of the power when the ground fails.
I have also been shocked by a perfectly 480 volt hoist motor in a bridge crane in a dry location. This is because motor winding insulation capacitance will leak some amount of 480 volts to ground even if the insulation is perfect. That is why U.S. National Electrical Code requires bridge cranes to grounded both through a dedicated runway conductor and the support rails and wheels.
I am pretty sure that some of you have also been shocked by a broken ground wire.
Long winded? Thanks guys and mine are often more so in long winded. Makes sense what it's purpose is.
By the way, speaking of mine safety... was listening to an interview on NPR the other day with a deep cave exploring scientest / caver. He was one of two teams exploring the two deepest ones - one in Mexico, the other somewhere in the Ukrane if I remember correctly. Mentioned one of the many ways one could die even in the deepest of caves - step in water during a lightning storm... even in the deepest of caves, a lightning hit over a mile under ground could still kill someone. Fascinating the ground path goes that far. That the case in a mine also or tunnel dig also? Do they not work during thunderstorms above?
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