RobertCX
Failed NEMA socket after 11 years use
Q. What happens to a Royce Thompson NEMA Rotaloc photocell socket after 11 years normal use?
A. It falls apart like this.
This socket formed part of an RS photocell kit, part number RS 571-439. Ironically, the photocell itself is fine, but the same cannot be said of the socket. I noticed that the photocell seemed very loose in the socket during routine maintenance, and after removing the assembly, found that the plastic housing had sheared away totally on two contacts, and partially on the third.
This suggests some form of materiels/manufacturing fault, and has been caused by repeated thermal expansion/contraction of the metal contacts against the plastic casing. The cell was mounted in a sunny location on the side of a building, hardly an abnormal situation for this kind of device.
Needless to say, it is not satisfactory, as the photocells themselves are designed to last up to 20 years, and the socket should easily do 40. It is also a safety hazard, as the plastic casing is no longer holding the contacts in place, so they could form a poor contact and result in arcing, heat and even an electrical fire.
I've contacted Royce Thompson about this via both email and letter, but so far they have declined to answer.
Their website has a datasheet for this socket at: www.roycethompson.co.uk/pdf/ACCESSORIES.pdf
This has the rather amusing quote: "The durable engineering polymer body houses Beryllium copper contacts which provide excellent wear properties for long service life". Whom are they trying to kid?
I now have a Zodion SS6 photocell installation, which appears to be of much better quality.
Failed NEMA socket after 11 years use
Q. What happens to a Royce Thompson NEMA Rotaloc photocell socket after 11 years normal use?
A. It falls apart like this.
This socket formed part of an RS photocell kit, part number RS 571-439. Ironically, the photocell itself is fine, but the same cannot be said of the socket. I noticed that the photocell seemed very loose in the socket during routine maintenance, and after removing the assembly, found that the plastic housing had sheared away totally on two contacts, and partially on the third.
This suggests some form of materiels/manufacturing fault, and has been caused by repeated thermal expansion/contraction of the metal contacts against the plastic casing. The cell was mounted in a sunny location on the side of a building, hardly an abnormal situation for this kind of device.
Needless to say, it is not satisfactory, as the photocells themselves are designed to last up to 20 years, and the socket should easily do 40. It is also a safety hazard, as the plastic casing is no longer holding the contacts in place, so they could form a poor contact and result in arcing, heat and even an electrical fire.
I've contacted Royce Thompson about this via both email and letter, but so far they have declined to answer.
Their website has a datasheet for this socket at: www.roycethompson.co.uk/pdf/ACCESSORIES.pdf
This has the rather amusing quote: "The durable engineering polymer body houses Beryllium copper contacts which provide excellent wear properties for long service life". Whom are they trying to kid?
I now have a Zodion SS6 photocell installation, which appears to be of much better quality.