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Old 01-04-2014, 04:57 PM   #1
apetay
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Default 1.5 amps vs. 3 amps DJL vs. DJA

sorry I'm a nooby, and I can't seem to find a straight answer. If I have a bulb socket that is rated 120v 150W 3amps, and there's another bulb with the same form factor, only difference is it's rated at 1.5 amps, can I use it as a replacement?

The bulb place says it's a "possible" match, and I don't mind if it is more dim, I just don't want to fry my projector. If I blow the bulb, at least I tried. It's an old Anscovision 88, but the mechanical is still good.

Swap in DJL for DJA
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Old 01-04-2014, 07:22 PM   #2
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Default Re: 1.5 amps vs. 3 amps DJL vs. DJA

The two lamps have different focal distances, a 1/2" difference to the filmgate, so the substitute lamp would give less light. I don't know the Ancovision 88 specs. Maybe a DFG?
DJA datasheet DJL datasheet Source: Don's Bulbs

The lamp socket rating is limited by two things- its heat rating for the socket and current rating for the connecting pins. Do you mean substitute a 3A (360W@120V) socket for a 1.5A socket (180W@120v)? That's okay.
Socket ratings depend on if the socket is ceramic or bakelight, and if there is a cooling fan, inrush current blah blah.

Don't upsize (double) the lamp wattage.... things will melt...
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Old 01-07-2014, 02:47 AM   #3
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Default Re: 1.5 amps vs. 3 amps DJL vs. DJA

Thanks redwire! This was the kinda answer I was looking for. DJA is the one rated for 3 amps that I know my projector can use, however I found some DJL's rated at 1.5 amps, for a very good price. Most of the "info" I saw said that the two had the same W and V ratings, and it was only the amps that were different. I think this is just typical internet disinformation, or I just wasn't paying close enough attention. What's this "inrush current" you speak of? The Ansco 88 does have a cooling fan, btw, and the badge clearly states DFP is a usable bulb as well as DJA.
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Old 01-07-2014, 09:42 PM   #4
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Default Re: 1.5 amps vs. 3 amps DJL vs. DJA

Quote:
Originally Posted by apetay View Post
Thanks redwire! This was the kinda answer I was looking for. DJA is the one rated for 3 amps that I know my projector can use, however I found some DJL's rated at 1.5 amps, for a very good price. Most of the "info" I saw said that the two had the same W and V ratings, and it was only the amps that were different. I think this is just typical internet disinformation, or I just wasn't paying close enough attention. What's this "inrush current" you speak of? The Ansco 88 does have a cooling fan, btw, and the badge clearly states DFP is a usable bulb as well as DJA.
Not "disinformation", but a flat out lie that defies the laws of physics.

Wattage "W" is calculated by Voltage "V" times Current "A"

120V x 3.0A = 360 Watts
120V x 1.5A = 180 Watts

Filament light bulbs have a much lower resistance when cold then they do when they are hot, so they pull allot more current at turn on then they do after they reach their normal operating temp. The current pulled by a cold bulb is the "inrush current". it only lasts a few milliseconds, but can be many times the normal current.
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Old 01-08-2014, 01:01 AM   #5
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Default Re: 1.5 amps vs. 3 amps DJL vs. DJA

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Originally Posted by LLLlllou View Post
Not "disinformation", but a flat out lie that defies the laws of physics.

Wattage "W" is calculated by Voltage "V" times Current "A"

120V x 3.0A = 360 Watts
120V x 1.5A = 180 Watts

Filament light bulbs have a much lower resistance when cold then they do when they are hot, so they pull allot more current at turn on then they do after they reach their normal operating temp. The current pulled by a cold bulb is the "inrush current". it only lasts a few milliseconds, but can be many times the normal current.
More real answers. Geez I love this forum!!!!
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Old 01-08-2014, 01:27 PM   #6
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Default Re: 1.5 amps vs. 3 amps DJL vs. DJA

Is this by any chance for a Super 8 projector??? Are you digitizing reels?
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Old 01-08-2014, 05:27 PM   #7
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Default Re: 1.5 amps vs. 3 amps DJL vs. DJA

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Originally Posted by apetay View Post
More real answers. Geez I love this forum!!!!
Mind you, that's not to say that every light that uses 360 watts puts out twice the optical output as every 180 Watt light. Comparing apples to apples, one tungsten filament bulb is going to be extremely similar to the next. Apples to oranges, Florescent bulbs put out about 2-3 times as much light per watt, and LEDs can double that again. If we ever find a way to turn electrons into photons with 100% efficiency, one watt would probably vaporize your retinas.


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Old 01-08-2014, 10:31 PM   #8
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Default Re: 1.5 amps vs. 3 amps DJL vs. DJA

These projector lamps are pushed pretty hard to get their 3200K color temp. CRI. They have only a 15hr life rating and I'm pretty sure they aren't halogen, as the halogen lamp (commercial) patent is 1959, took a while to make "hard" glass. I think 8mm projectors were popular in the late 1960's.

Modern DLP projector lamps are 1,000-2,000 hour life rated but expensive. It might be worth hacking one into an old projector?

Source: "Revolution in Lamps: A Chronicle of 50 Years of Progress" ISBN 0-88173-378-4
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Old 01-09-2014, 11:45 PM   #9
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Default Re: 1.5 amps vs. 3 amps DJL vs. DJA

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Originally Posted by mockingbird View Post
Is this by any chance for a Super 8 projector??? Are you digitizing reels?
Yes indeed on both accounts- I'm digitizing some early 70's home movies for my Mom's birthday.

This project's been on the back-burner for a long long time. I've considered trying to wire in some LED's, but 15 hours of standard bulb life would likely get me by...
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Old 01-10-2014, 01:23 AM   #10
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Default Re: 1.5 amps vs. 3 amps DJL vs. DJA

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Originally Posted by LLLlllou View Post
Mind you, that's not to say that every light that uses 360 watts puts out twice the optical output as every 180 Watt light. Comparing apples to apples, one tungsten filament bulb is going to be extremely similar to the next. Apples to oranges, Florescent bulbs put out about 2-3 times as much light per watt, and LEDs can double that again. If we ever find a way to turn electrons into photons with 100% efficiency, one watt would probably vaporize your retinas.


If it's one thing I don't need help with vaporized retinas! I'm sitting at 20/200 unassisted.

Last edited by apetay; 01-10-2014 at 01:25 AM.. Reason: continuity
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