When wiring a 3 phase AC motor I need to connect 3 phase lines and neutral from the 3 phase socket to the motor. Motor has 3 lines and a ground symbol on it to power up. But the socket is 3p+E+N socket. I cannot determine which is earth which is neutral. Does that matter? Are they(neutral and earth) internally connected. Here is the socket: http://www.distributionzone.com/store/industrial-plugs/product-straight-plug-3p-n-e-400v-63a-ip67-035-6-41/
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Yes it absolutely does matter! For safety, the neutral is only bonded to earth at the building service entrance.
The diagrams under the "Additional Information" tab on the page you linked to seem pretty clear. What part is confusing you?
Dave Tweed
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2 things. 1) on the 3 phase motor there is a ground symbol. is that for earth or neutral? 2)which pin is earth which is neutral on the socket? – user16307 Jul 22 '14 at 17:56
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ground = earth. – Dzarda Jul 22 '14 at 18:38
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Ans about 2): As said, there's a picture under the "Additional information" diagram, just scroll down. PE=earth, N=neutral. – sweber May 28 '15 at 07:16
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Have a look at the IEC 60309 standard, there are several types of plugs defined, based on the number of wires (5 here) and the position of the earth (e.g. 6h for 6 o'clock). They are color coded too. Legrand has pretty good datasheets otherwise.
Your motor needs 3 wires plus the earth, its windings are wired between phases so the neutral does not matter:.as long as the windings are identical, the neutral current is mathematically zero. If one of them breaks however the absence of neutral will increase the power consumption as the supply will be unbalanced (see unbalanced three phase). But your motor doesn't have a neutral plug does it?
The earth is only to earth the chassis, such that if the chassis is energised it creates a fault current that is immediately detected by the residual current device and trips it.
The standard connectors don't wire anything internally, it is done upstream if the earthing scheme of your country requires the neutral to be earthed.
Mister Mystère
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Note also that most three phase machines can be configured for either star or delta connection depending on what the phase voltage is, but in basically no case do they require a neutral. – Dan Mills Jan 23 '17 at 10:54