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Author Topic: IREM Rectifier problem
Joseph Muggio
Film Handler

Posts: 9
From: Dauphin, PA, USA
Registered: Oct 2006


 - posted 08-06-2008 12:10 PM      Profile for Joseph Muggio   Email Joseph Muggio   Send New Private Message       Edit/Delete Post 
Can anyone help me find a distributor that carries parts for an IREM N3-X75DM Rectifier. The local semi-conductor vendors in my area have all said they don't know where to go after I showed them the specs from the manual. The only thing I did find was the diodes. There's still a ripple in the light output on-screen. (By the Book)there are 6 capacitors, an ignition relay, some fuses and an output cap. that are recommended for spare parts. I used to be able to just turn the Rectifier on and the bulb would light. That no longer happens. Now I have to use the ignition switch on the back of the lamp house (Super Lumex)in addition to the rectifier power switch. So I'm guessing that the ignition relay also needs replaced. Maybe the electrolytic output cap needs replaced. I don't know. Anybody know what else needs to be checked and where I can find these parts. Thanks.

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Louis Bornwasser
Film God

Posts: 4421
From: prospect ky usa
Registered: Mar 2005


 - posted 08-06-2008 01:02 PM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
Any repair of this will start with measuring the DC voltage off the recttifier BEFORE you push the igniter. If you changed all 6 diodes, you should be OK. I rather suspect the lamp, but the DC no load voltage will tell the tale.

All part are available from any reputable dealer. We are Hadden Theatre Supply. Louisville, KY Louis

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Joseph Muggio
Film Handler

Posts: 9
From: Dauphin, PA, USA
Registered: Oct 2006


 - posted 08-06-2008 01:23 PM      Profile for Joseph Muggio   Email Joseph Muggio   Send New Private Message       Edit/Delete Post 
We've changed all 6 diodes and still have a noticeable output ripple. I'm pretty sure it's gotta be the rectifier. The DC load voltage meter on the back of the lamphouse originally showed about 60-65V. After we increased the output to 75 (which is where it should be) it slowly drops in voltage, but just wont hold steady. We've tried changing the bulb and it still does the same thing.

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Louis Bornwasser
Film God

Posts: 4421
From: prospect ky usa
Registered: Mar 2005


 - posted 08-06-2008 07:15 PM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
Carefully move all large wires on the terminal panel on the rectifier. You are looking for a loose connection.

While I have never (in 30 years) changed capacitors, they DO fail. Also the RA relay can cause these problems. "Unplug it" and connect red to red, black to black. If it works, order a new RA relay. Louis

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16059
From: Bountiful, Utah
Registered: Jun 99


 - posted 08-06-2008 07:24 PM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
Always start at the beginning, not near the end of things... You might first check to see if you've lost an incomming phase... er leg of power. Not only would that cause the flickering but it will also make it difficult to start the lamp because of lower no-load DC voltage. Bad contactors are VERY common on IREM recifiers!!! The contactors they come with are really meant for higher voltage 380 three phase as they have in Europe... which results in lower AC current across the contactor.

Mark

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 11986
From: Annapolis, MD
Registered: Dec 1999


 - posted 08-06-2008 08:45 PM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
I think I have seen it all on IREMs...I've had bad diodes, bad RA relays (called A1 relays on new "US", Non-"X" version...they are NOT the same board but similar function), bad capacitors!

I've had old IREMS that never needed a new capacitor (in the sense of one failing out right) and I've had newer ones...with about 3-years time, have a boost cap shoot its cookies (in two different rectifiers). Note the current ones have a safety breaker that will trip and take the capacitors off-line...there is no notification and the lamp may still strike but the life will be horrible!....Come to think of it, I've had the stupid breaker fail too!

As Mark says...the ABB contactors have historically been under-rated for US use. Older ones would be part of the "B09" series...later ones have been of the A10 series and even later ones are now of the A16 series (for a 2K rectifier such as the one described here). If sticking with ABB contactors, don't go for less than an A26 or you might be buying more very expensive contactors. The problem arises that in the US, the line voltage is typically between 200-208VAC.....not 230 and definately not 380. Power-In = Power-Out (it is one of the golden rules of electricity)....so as the voltage drops in value, the current goes up and that tends to eat the contactors that are marginally rated or flat out under-rated. If you read an ABB spec sheet, the A series pretty much reads what the current/leg rating is. That is an A16 is really only rated at 16A leg (and note, the 4th pole is only a switch leg and not rated as high as the main ins/outs). Measure the current on any leg feeding a 2K rectifier...I'll wager you are at or over 16A if everything is tuned up properly. An A16 is a failure waiting to happen. Go to an A26 or A30 and the problems go away. For the 3Ks and Up...An A40 or A50 should be preferred over the stock A30. Though I think I'm seeing A40s now in the N3-180s (not that it will do 180A...it only does 165A).

Anyway...everything should be suspect. I would plan on a full capacitor change...even if they have not failed...they are likely 10-years old or more and thus have lost some capacitance. Changing them will improve the ripple, period. This is true for all rectifiers. I will generally change the main filter caps if there is any suspect of ripple by viewing the aged xenon lamp...new caps always seem to improve the life considerably and they are relatively cheap for the improvement they bring (should pay for themselves on the next lamp by not having to change it so soon).

RA-relay must also be functioning properly in an IREM or the capacitors will not be switched in properly. If you have many IREMS of this vintage, I would get an RA relay because even if it isn't causing you grief, it will be at some point.

Steve

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John Walsh
Film God

Posts: 2490
From: Connecticut, USA, Earth, Milky Way
Registered: Oct 1999


 - posted 08-06-2008 09:38 PM      Profile for John Walsh   Email John Walsh   Send New Private Message       Edit/Delete Post 
Agree with everyone, but I'd like to add a few things ... The no load voltage on newer IREMs is around 95 volts (the older units are 75v.) Apparently, about 10-15 years ago, the pressure and gas was changed in xenen bulbs to get brighter light, and this required a higher voltage to get them to ignite. That is why some newer bulbs have a hard time lighting in older IREMs.

Also, the contactor coil in IREMs has failed many times because the installer fails to notice the building has a wild-leg phase, and connects the high leg to one side of the 220v coil, rather than the 'transformer input only' terminal, thus placing 300v or more across the coil.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16059
From: Bountiful, Utah
Registered: Jun 99


 - posted 08-06-2008 10:39 PM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
John,

I was told by someone over in Europe that the older Irems are actually wound for 380 volts 3 phase which is the standard over there and that the later breed is actually would for the North American standard 208 3-phase. Have you heard this?

Mark

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Tony Bandiera Jr
Film God

Posts: 2931
From: Moreland Idaho
Registered: Apr 2004


 - posted 08-06-2008 11:09 PM      Profile for Tony Bandiera Jr   Email Tony Bandiera Jr   Send New Private Message       Edit/Delete Post 
quote: John Walsh
....because the installer fails to notice the building has a wild-leg phase, and connects the high leg to one side of the 220v coil, rather than the 'transformer input only' terminal, thus placing 300v or more across the coil.
Sorry to disagree John, but wild leg voltage will be highly variable, but usually in the range of 180-240v max. (typically seems to be found hovering near 208v), measured from the phase to neutral. Phase to phase from the wild leg to either of the other two phases will always be 220-240 volts. So a 220 volt nominal coil would be ok with wild leg until it drops below 200 or so.

Of course all bets would be off if the coil is rated at 120 volts. [Smile]

I speak from over 20 years of experience as an electrican as well as cinema tech. [Smile]

To the OP and the problem he's having, I agree with the previous posts to check incoming power, the contactor and the heavy DC cables in that order.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 11986
From: Annapolis, MD
Registered: Dec 1999


 - posted 08-06-2008 11:34 PM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
The coil rating on the ABB breaker as found in an N3X-75 is going to be upwards of 240VAC but runable down to about 190VAC. They aint that fussy.

Like all contactors, they can come with different coils and look identical. I believe with ABB, the coil is the 4th part of its Part number...that is...with an A30-30-10-80...it is the "80" that denotes the 240VAC coil. You normally only see the A30-30-10 part since those numbers relate to top portion of the contactor (contacts, aux contacts, poles...etc). ABB does make variants though specific for 208VAC, 220 as well as the standard 240VAC coils.

If the 4th part of the number is "84" then it has the 120VAC coil.

Steve

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Stephen Furley
Film God

Posts: 3045
From: Coulsdon, Croydon, England
Registered: May 2002


 - posted 08-07-2008 02:11 PM      Profile for Stephen Furley   Email Stephen Furley   Send New Private Message       Edit/Delete Post 
quote: Mark Gulbrandsen
John,

I was told by someone over in Europe that the older Irems are actually wound for 380 volts 3 phase which is the standard over there and that the later breed is actually would for the North American standard 208 3-phase. Have you heard this?

Mark

Mark, What do you mean by 'older'; how old, and are you talking about ones sold over there, or in Europe? The Irems that I've seen here, do seem to be stamped 380V. The ones at the Clocktower are 13 years old, these are 380V, and are probably the newest that I've seen, but older ones elsewhere seem to be 380V as well.

The Voltage in the UK was standardised at 240/415V by the very early '60s, I just remember having 200V single phase at home, or rather I just remember it being changed, I was too young to understand such things at the time. The reason I know that it was 200V was that one or two seldom used 200V light bulbs, plus a couple of spare ones which were never installed survived long enough for me to have seen the Voltage stamped on them.

From this time we were 240/415V +/- 6%. Mainland Europe was mainly 220/380V, though there were some places with small variations from this. I'm not sure what the tolerance was. Under a 'harmanisation' directive, probably about ten years ago now the declared Voltage was changed to 230/400V throughout Europe, and the tolerances widened to include the previous Voltages, so nothing actually had to change. Just about everybody here still seems to call it 415, but newer warning signs and labels do now say 400V. We went from 240/415 +/- 6% to 230/400 +10/-6%. There were proposals for this to become 230/400 +/- 10%, but I'm not sure if this ever happened. I haven't seen an Irem stamped either 400 or 415V, all the ones which I've looked at have been 380V.

Are you saying that the older ones over there are 380V? This seems unlikely, since this is much further further from any of the three phase Voltages you have over there than the difference between 380/400/415V. When you mention 208V three phase I assume you are talking about a 120/208V wye (we would call it star over here) system; this is basically a half-Voltage 60Hz. version of what you would find throughout Europe. You would not normally find a delta system in a supply to a consumer here, you would only find it used for high-Voltage transmission and distribution lines.

Irem rectifiers are very common here; my experience with them has been very good; never had any problems at all.

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