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Graflex Solenoid.
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clnfrd



Joined: 26 Mar 2002
Posts: 616
Location: Western Kentucky Lakes Area

PostPosted: Wed Dec 04, 2002 4:10 pm    Post subject: Reply with quote

If the number on the solenoid denotes the voltage it's designed for...I'd still like to know what voltage should be used with my Graflex Solenoid # 0. Thanks. Fred.
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Les



Joined: 09 May 2001
Posts: 2682
Location: Detroit, MI

PostPosted: Wed Dec 04, 2002 6:30 pm    Post subject: Reply with quote

.....and I'm still looking though my reference material. I'll swear I ran accross it before. Maybe somebody with better computer skills can search the original helpbboard database.

Can you tell me what camera it came off of? Pacemaker? Super? Anny? Just off the top of my head, I'm wondering if they made a #0 late in life just to trigger sync'd shutters. It could be used with either 2 or 3, and the delay would be variable but it wouldn't matter as the shutter was timing the flash.

No evidence of this, just a thought.

[ This Message was edited by: Les on 2002-12-04 10:33 ]
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clnfrd



Joined: 26 Mar 2002
Posts: 616
Location: Western Kentucky Lakes Area

PostPosted: Wed Dec 04, 2002 8:50 pm    Post subject: Reply with quote

Les, the solenoid was in a box of assorted flash gun parts including the huge DeMornay Budd I bought, so I don't know what camera it was originally mounted on, if any. It looks new...has the typical adjustment for syncing...and the usual 2-pole female connection. I arbitrarily applied three volts to it and it instantly pulls in just like it should, although I haven't tried to use it for flash sync yet. I'd like to try to mount it on a 2X3 lensboard with a Graphex or Rapax I have, so the whole assembly could be removed in case I wanted to switch to another shutter with X-sync. Fred. P.S. Additional info: the solenoid has a heavy bracket for mounting to the lensboard or standard with two tapped holes in the "foot". One is visible from the front...both from the rear. They are slightly off-set 9/32" apart. They are for a #1 machine screw. However, I tried a 1-72 and it only goes in about a turn and binds. It appears the threads are a little coarser than 72. Fred.

[ This Message was edited by: clnfrd on 2002-12-04 13:50 ]
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alecj



Joined: 09 May 2001
Posts: 853
Location: Alabama

PostPosted: Wed Dec 04, 2002 10:05 pm    Post subject: Reply with quote

In my Graflex service manual, in the solenoid section, the two remaining models available are the 2 and the 0. The 3 is shown as discontinued as of that time ('64). But nowhere in the document is the difference between any of them shown. That seems to support your supposition, Les, that it was a later model.

I'd suggest an inquity to Fred Lustig. I bet he knows.
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clnfrd



Joined: 26 Mar 2002
Posts: 616
Location: Western Kentucky Lakes Area

PostPosted: Thu Dec 05, 2002 9:59 pm    Post subject: Reply with quote

It's my honest opinion, being an old (very old) electronics technician, that for intermittent duty, 3 or 4-1/2 volts can be used on this solenoid without exceeding the rating of the enameled wire used to wind the coil. The pull in time will vary, but I woild think it should be adjustable enough to achieve flash sync with either a 2 or 3-cell gun. I was just curious about the #0 and why they used that. Think I'll just play with it and not bother Mr. Lustig. Thanks for your help. Fred.
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Les



Joined: 09 May 2001
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Location: Detroit, MI

PostPosted: Fri Dec 06, 2002 12:29 am    Post subject: Reply with quote

One thing I've heard / read was Graflex said you can't mix them or bad things will happen. If you run a #3 on 2 cells it won't pull hard enough, and if you run a #2 on 3 cells in will pull too fast.

And yet I have a 1940 Anny with the original lens solenoid and flash--- its a #2 with a 3 cell-- and it works perfectly.
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45PSS



Joined: 28 Sep 2001
Posts: 4081
Location: Mid Peninsula, Ca.

PostPosted: Fri Dec 06, 2002 3:16 am    Post subject: Reply with quote

Quote:

On 2002-12-05 16:29, Les wrote:
One thing I've heard / read was Graflex said you can't mix them or bad things will happen. If you run a #3 on 2 cells it won't pull hard enough, and if you run a #2 on 3 cells in will pull too fast.

And yet I have a 1940 Anny with the original lens solenoid and flash--- its a #2 with a 3 cell-- and it works perfectly.

I wonder how much battery design of that day vs today affects preformance.
Charles

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Les



Joined: 09 May 2001
Posts: 2682
Location: Detroit, MI

PostPosted: Fri Dec 06, 2002 4:55 am    Post subject: Reply with quote

I've wondered about that too. My dad (class of '41) remembers that batteries of the day died quickly on the shelf and didn't last that long in use.

A far cry from what we have today.

And yet I've been plagued by the same problem...you've got to use fresh batteries or you'll have trouble. Using the same batteries from last month is asking for trouble.
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clnfrd



Joined: 26 Mar 2002
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PostPosted: Fri Dec 06, 2002 1:48 pm    Post subject: Reply with quote

No, you shouldn't mix 2 and 3-cell units with the same solenoid set-up once you get your sync correctly adjusted. However, logic would dictate that once you have adjusted the solenoid to sync your flash with your shutter with a 2-cell...even if it's designed to operate a 3-cell...or vice-versa...it should work if you keep fresh batteries installed and the terminals clean. A solenoid is an electromagnet energized by the voltage to pull in the plunger. Pull-in time will vary in microseconds with varying voltages. Battery voltage will vary with the type of battery used. Nicads...alkaline...zinc-carbon, etc. do not produce the same exact voltage. Nicads, for example, are well under 1.5 volts. So whatever you use...be consistent or the sync may suffer. Fred.
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45PSS



Joined: 28 Sep 2001
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Location: Mid Peninsula, Ca.

PostPosted: Sat Dec 07, 2002 4:02 am    Post subject: Reply with quote

My consern was the current ability of the batteries of varring ages. The internal resistance of the battery affects how much current it can produce and I'm not familuar with how to caculate it, so, If batteries of old could only produce a current of x amount then it would require y of them to operate a selonid that could handle only z current. If new batteries are an improvement then they can produce x+?% current requiring y-? of them to do the same job.
If any given selonid can only handle 300ma of current and you connect a power source that produces 350ma of current then it will burn out quicker than it would have if the 300ma limit had not been exceded.
Charles

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clnfrd



Joined: 26 Mar 2002
Posts: 616
Location: Western Kentucky Lakes Area

PostPosted: Sat Dec 07, 2002 12:19 pm    Post subject: Reply with quote

Just because you have a power source capable of a given current doesn't mean that much current is dumped through the load. For example, just because your home has a 200-amp service doesn't mean that 200 amps is dumped through an appliance or light bulb when it's turned on. A load requires a certain amount of power:watts. Power (watts)=E(voltage/electromotive force) X I (current/amps). The current is the amount of electrons flowing through a load and is limited by its resistance. According to ohms law: I=E/R. In other words, the current flowing in a load is determined by the voltage applied divided by the resistance. However, if you apply more voltage than its rating, you can exceed the current rating of the wire and burn it out. Where solenoids are concerned, I can't conceive of any manufacturer using enameled wire to wind the coil that would burn out if you use three cells instead of two. Headroom is always calculated into any design. I would rather think that the coil of a 3-cell solenoid would be designed to operate most efficiently to pull in the spring-loaded plunger at 4.5 volts...and the 2-cell model operate most efficiently at 3 volts. I would bet the coils are the same and the spring tension is what is different. Fred.

[ This Message was edited by: clnfrd on 2002-12-07 05:36 ]
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45PSS



Joined: 28 Sep 2001
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Location: Mid Peninsula, Ca.

PostPosted: Sun Dec 08, 2002 6:03 am    Post subject: Reply with quote

Ferd,
I bet you, Les and myself have brought to light most of the most likely failures and things to be causious about reguarding selonids.
I have a #2 that I do not ues, maeby I'll put three cells to it or better yet one of the 3 cell handles I have and see how long it takes a fresh set of batteries to burn it out.
Charles

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clnfrd



Joined: 26 Mar 2002
Posts: 616
Location: Western Kentucky Lakes Area

PostPosted: Sun Dec 08, 2002 3:16 pm    Post subject: Reply with quote

Just remember that solenoids are designed for continuous OR intermittent duty. Those for intermittent duty are wound with lighter wire for compactness and economy. The Graflex is probably for intermittent duty which means if you kept it energized for a long period of time you could over-heat the wire and melt the enamel insulation which would cause the winding to short out. So don't hold the trip button down for any longer than necessary to trip the shutter. FWIW, my reference to ohm's law was an over-simplification of what determines current flow in a magnetic coil. Since a coil is an inductor, the resistance of the wire AND the inductive reactance of the magnetic field determine the current flow. Bottom line: if the adjustment on your #2 solenoid allows you to achieve flash sync with a 3-cell, go for it...but just pulse it momentarily so as not to over-heat the coil. Fred.
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Daryl J



Joined: 11 Oct 2002
Posts: 11
Location: Wyoming

PostPosted: Thu Feb 13, 2003 4:34 pm    Post subject: Reply with quote

I think we need to keep in mind that there are other variables besides the solenoid design which affect the pull-in time. Specifically, the flash bulb is actually in parallel with the solenoid. When you push the red button on the back of the Graflite, you apply voltage to both the bulb and the solenoid at the same instant. The solenoid is intented to trip the shutter in 20ms , which provides time for the bulb to reach full brilliance. Therefore, when setting up the solenoid, a load needs to be in the flash bulb socket to simulate the flash bulb load. I've measured the resistance of #5 bulbs (a good thing to do before you use them) and they typically run about 0.8 Ohms. When fired by a 3 cell Graflite, the means almost 6 amps of current is momentarily going through the bulb, which pulls the battery voltage down quite a bit. In other words, the flash bulb provides most of the load. Using remote flashes puts even more load on the batteries. That's why the capacitor discharge system was developed. As we know, Graflex sold battery extenders for the Graflite so you could go to 4, or even 5 cells when needed.

Some years back I borrowed a storage oscilloscope from work and did some experimenting. I used a 3 cell flashlight bulb to simulate the flash bulb load. I was able to determine that the delay provided by the solenoid changed very little when going from 3 to 4 alkaline D cells. Certainly not enough to have any effect on exposure. If I know my batteries are getting a little weak, or I'm shooting in cold weather, I just screw on the extender and add another D cell.
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clnfrd



Joined: 26 Mar 2002
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Location: Western Kentucky Lakes Area

PostPosted: Thu Feb 13, 2003 9:46 pm    Post subject: Reply with quote

Good info, Daryl. For all practical purposes, a cold filament is a dead short. The momentary in-rush of current is great indeed. With a flashlight bulb, of course, as the filament heats, the resistance increases, so the short is only momentary. With a flash bulb, the instant the oxidation of the magnesium wire commences, the short is removed. Your point of the flashbulb and its current demand being in parallel with, and at the same instant, as the current demand of the solenoid is well taken. And, as you have pointed out, apparently the nanosecond differential with varying voltages as concerns the energization of the solenoid is not that big a factor in the real world as long as you use fresh batteries, or, better still, a system that employs capacitive discharge. You must have a quality ohm-meter to get an accurate reading below 1 ohm. I used a Wheatstone bridge and/or a Fluke Meter with low-ohms scale and very sharp probe tips in my work. Fred.
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