Film-Tech Forum ARCHIVE: Choke value for Strong 61000 power supply

This is topic Choke value for Strong 61000 power supply in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Ian Parfrey (Member # 5122) on 05-04-2012, 11:15 PM:

I'm in need of getting a rewind done on the choke for a Strong 61000 power supply and need the value so I can get the work done.

Would any one know what the Inductance and resistance values are for this choke?

Cheers
Ian

Posted by Tony Bandiera Jr (Member # 2365) on 05-07-2012, 12:02 AM:

Why does it need to be rewound? Burned up, water or other physical damage, or noisy?

Any competent transformer shop can, if all the original windings are there (even if badly damaged), rewind it properly.

If the laminated core is ok you can even rewind it yourself following a few simple rules:

1: Use same gauge and insulation type of wire;
2: Wind the exact same number of turns in the same direction and laydown pattern of the original;
3: Dip the finished assembly in transformer varnish and bake it to dry it out.

Only Strong would know those values and good luck getting them to tell you. [Roll Eyes]

Posted by Ian Parfrey (Member # 5122) on 05-07-2012, 12:14 AM:

Thanks for the suggestions, Tony.

It's got an open winding and I was hoping to have a bash at winding a replacement coil.

I did find an onsite calculator for winding chokes which is here for posterity. D.C choke winding formulas.

I haven't yet tried Strong for the choke specs, but based on your advice I may well forget that line of action.

Many Thanks for the suggestions... I'm off to get this thing sorted.

Posted by Tony Bandiera Jr (Member # 2365) on 05-07-2012, 12:24 AM:

You're welcome and best of luck to you.

Making sure I am clear since you didn't give specifics (and I am very tired as I was working in Corona getting set up for my annual Renaissance Fest) are we talking a heavy output choke on a magnetic rectifier or a choke on a switching rectifier's control board?

Reason I am asking is that if it is an output choke wound with heavy-guage wire the tolerances are not very critical and a do-it-yourself attempt has a high chance of success.

One of the smaller chokes on a switcher's control circuitry however has to be done just right or it may fail to work properly or even cause damage to the control electronics.

If you can post pics of the choke in question and it's location in the rectifier that would be helpful.

Posted by Gordon McLeod (Member # 33) on 05-07-2012, 08:27 AM:

Unwind the old choke measure the length of wire and cut a piece of the same guage and length and rewind it onto the core and it will be almost the same
Remember at best large currents chokes are often 10% tolerance

Posted by Ian Parfrey (Member # 5122) on 05-21-2012, 06:58 PM:

Update.

I gave up trying to get any values out of Strong and so tried Gordon's method and all is now well...not much fun but successful nevertheless.

Thanks Guys! [thumbsup]

Posted by Louis Bornwasser (Member # 3063) on 05-21-2012, 07:24 PM:

Is this the 2Kw single phase, high reactance unit? If so, they added an (unnecessary) choke on some models. I have removed it with no ill effects. It was noisy due to the magnetic effect of its mounting.

Remember, I live in 60 Hz land. louis

Posted by Ian Parfrey (Member # 5122) on 05-21-2012, 11:24 PM:

That's the unit, Louis.

They aren't much quieter here in Slow Power land either.

Knowing what you have said, I'll try the same thing and see how it runs.

Many Thanks

Posted by Sam D. Chavez (Member # 1841) on 05-22-2012, 12:21 AM:

Strong did an all around bad job on the construction of the chokes but the idea was to improve the inrush current and the ripple. These are both critical to long bulb life with no flicker.

I would be careful about removing it without some thought about these issues.

Posted by Ian Parfrey (Member # 5122) on 05-22-2012, 02:48 AM:

I was thinking about beefing up the filtering caps. Granted, that would increase the inrush but the output smoothing would be a bit better.

Posted by Louis Bornwasser (Member # 3063) on 05-22-2012, 06:52 AM:

Whenever I have something fail in a 50 Hz country, I blame it on "slow electricity." Louis