R40 -R50 Differences

[Usenet Nutter]

I have a couple of light fittings which use reflector bulbs ,R40's I think . I recall using a R50 in one of them years ago as that was all I had and it didn't work . I know have another lamp which also takes SES reflector bulbs and it won't work with the one bulb I have in the house ....I gave the others away when I changed the kitchen light recently . I do know the bulb works as I used it in a Lava Lamp and it lights and it is a Philips Spotone 30 which Google tells me is an R50

Now what I want to know is what physical difference is there between R40's and R50's that mean one works and one doesn't in these fittings .Anyone know? R40's seem not to be available now.

[Dave Osborne]

Well,

The R tells you it's a reflector lamp and the 40 tells you that the diameter of the lamp is 40 eighths of an inch (i.e. 5"). Ditto R50, except that the diameter is 6 1/4"

R40 tells you nothing about the voltage, wattage, beam angle, cap size (ES, SES, etc), colour, frosting or anything else.

Assuming that the physical size of your R50 wasn't a problem, then either your R50 was duff, or possibly, the fitting needed the tab for the centre connection to the bulb to be cleaned or bent out a little.

HTH

[Usenet Nutter]

I think you mebbe got the first bit wrong ..or at least not correct for what I have ....this one bulb have is 2" across the top which is about 50mm This the Philips Spotone 30 which ,as I said ,Google says is an R50 although I believe you do get similar lamps in much larger sizes. This lamp does work as I said .It just doesn't work in the two lights I have that takes this type of lamp( or mebbe only R40's)

HOWEVER

Your last suggestion was spoton ( or should that be Spotone) .It was the contacts in the lampholders that were the problem ..a slight tweak with a thin screwdriver and the job was done ... thx very much Dave.:-)

[Dave Osborne]

OK, the eighth-inch numbering system is conventional for some lamps including R, RO, PAR, prefix, etc which are based on American patterns.

For others, the number is the nominal lamp diameter in mm. Sorry I neglected to mention this.

I confess I didn't look up the Philips Spotone product which would have brought the inconsistency to light.

Glad to be of service.