New member

[JoeinRI]

Hello everyone,
I'm a new collector and new to this site.  My name is Joe and reside in Rhode Island. I've been an avid collector/restorer of antique radios for a  couple of years now. My collection of radios has grown and I'm running out of room!  I've recently started to collect antique bulbs (I believe that they compliment the antique radio collection).
A recent purchase I made was that of a variac. i'd like to set a few bulbs in different locations on one wall...in between my radios. One of the problems is....not sure what I've got here in regards to bulbs. Should these bulbs be burned upright or hanging down? Does an evacuation tip on top of bulb mean that it pre-dates a certain year?
I'm careful not to apply too much voltage to the bulbs I have, although i belive them all to be 110V bulbs.
I did recently pick up an Edison/Mazda pricing booklet dated June 1, 1928 - clearly showing (at least the shapes of some of my bulbs)...and most are rated at 110V
I have one that appears to be a Street Light bulb from around 1928 with mogul base.  Is it possible to get adapaters for a mogul base bulb to fit in a medium base socket. I've seen the other way, but not medium to mogul.
From my readings on different sites....it seems to be very difficult to date some of these bulbs.

Thanks in advance for any help you can provide.
Joe

[adam2]

I doubt that you will find a mass produced adapter to use a mogul hase bulb in a standard socket, one of the reasons for the different size bases was to stop people useing lamps of excessive power in domestic and similar fixtures.

Regarding your mogul base bulb, possibly for street lighting, does it have a voltage marked on it ? if not be very cautious.
In years gone by, street lighting used lamps rated by candle power and amps, not by voltage. Large numbers of such lamps were burnt in series from a relativly high voltage supply such as 480 volts. Common current ratings were 6.6 amps and 15 amps. The voltage accorss each lamp was very low, from about 10 volts up to about 50 volts dependant on current and candle power.
Such a lamp would be instantly destroyed if connected to line voltage.
If you suspect that a lamp is for series burning, try connecting it to a 6 volt lead acid battery (alkaline cells cant supply enough current for most types)

Lamps for series burning are still made today, including modern halogen types. The main application is airport runway lighting.

[JoeinRI]

Thanks Adam! I'll keep that in mind when considering trying to power it up.  I do have the variac - 7A...capable of supplying low voltage. Would the bulb be drawing too much current trying it out that way? Thanks again for your advice to a novice newcomer!
Joe

[adam2]

A bulb that draws more than 7 amps should not be continualy powered from a 7 amp variac since the unit would be overloaded. Note that  it  is the variac not the bulb that would suffer.
A variac can easily supply twice the rated current for a brief test, therefore if your bulb is a series type rated at 6.6 amps it would be fine continually, and if rated at 15 amps it would be OK only for a brief test.

Or of course the bulb may be a regular type not a series one.