sitelights
02-26-2004, 01:02 AM
The attached image is overscale for detail; the actual dimensions are: base 9/16" high X 1 3/16" diameter; socket 1 5/16" high X 1 3/16" diameter. The base (a disc) and socket (a truncated cone) are made of ceramic; the clip is stainless steel and adds a half inch to the height of the socket. By comparison the socket with clip shown attached to the "MR16 clip socket" post on the Lamps (light bulbs) & sockets forum is 3/8" high (7/8" with the clip) and 3/4" diameter. In volume I estimate the MSD socket is 6 times as large as the clip socket. Both the MSD and the clip accomodate GY6.35 pin spacing so both can hold 35w bi-pin or MR16 lamps. Note that the MSD clip stabilizes the base of the bi-pin lamp but it does grip the base as it does on a MR lamp.
Full disclosure: I have a real problem with these replaceable sockets: the now-defunct Hadco MR socket with quick-connects (basicly minature male/female friction fit lugs) AND the MSD twist-and-lock socket.
Normally sockets are attached to the lead with crimp/cap connectors or butt splices; both methods provide a solid mechanical connection. These pressure-set splices positively join the wires: there is no "play" and they are not readily pulled apart. Quick-connects just slide together so they can just slide apart; the MSD socket mates with its base when the male "Frankenstein" headed pins rotate into the female keyhole slots and ramp together. I will admit that the last thing you feel as you rotate the socket into the base is a satisfying "over center" click but wiggle it and the socket rocks in its base.
I have been trying not to repeat myself on many detailed points so I refer you to the post "quality" within the "white lab coats" thread on the Engineering forum. As stated in that post, replaceable sockets add one more point of failure to a low voltage lighting system.
Yes, an MSD socket can be replaced in 30 seconds if you can get at it quickly but if the lamp pins were a mechanical join to the socket via set screws there would be no need to replace the socket. Set screw sockets to capture MR lamp pins have been a feature of cable-hung interior low voltage fixtures for 20 years; it eliminates the need for a "tether" for the lamp (usually a spring clip that grips the lamp reflector not the pins) if it falls out. Bi-pin lamps are too light to drop out of a socket accidentally even on impact but set screw sockets would vastly improve contact.
To my mind the size, weight and cost of an MSD socket is overkill. If a purpose-built, positive connection lamp socket with set screws was available it would eliminate the socket failures that are the cause for replacement. Why not get to the heart of the problem instead of adding another questionable quick fix?
Full disclosure: I have a real problem with these replaceable sockets: the now-defunct Hadco MR socket with quick-connects (basicly minature male/female friction fit lugs) AND the MSD twist-and-lock socket.
Normally sockets are attached to the lead with crimp/cap connectors or butt splices; both methods provide a solid mechanical connection. These pressure-set splices positively join the wires: there is no "play" and they are not readily pulled apart. Quick-connects just slide together so they can just slide apart; the MSD socket mates with its base when the male "Frankenstein" headed pins rotate into the female keyhole slots and ramp together. I will admit that the last thing you feel as you rotate the socket into the base is a satisfying "over center" click but wiggle it and the socket rocks in its base.
I have been trying not to repeat myself on many detailed points so I refer you to the post "quality" within the "white lab coats" thread on the Engineering forum. As stated in that post, replaceable sockets add one more point of failure to a low voltage lighting system.
Yes, an MSD socket can be replaced in 30 seconds if you can get at it quickly but if the lamp pins were a mechanical join to the socket via set screws there would be no need to replace the socket. Set screw sockets to capture MR lamp pins have been a feature of cable-hung interior low voltage fixtures for 20 years; it eliminates the need for a "tether" for the lamp (usually a spring clip that grips the lamp reflector not the pins) if it falls out. Bi-pin lamps are too light to drop out of a socket accidentally even on impact but set screw sockets would vastly improve contact.
To my mind the size, weight and cost of an MSD socket is overkill. If a purpose-built, positive connection lamp socket with set screws was available it would eliminate the socket failures that are the cause for replacement. Why not get to the heart of the problem instead of adding another questionable quick fix?