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Turning motor fast trips out sled power


Ed Moore

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Hi guys,

 

The other day a strange thing was happening. I was powering a RED, a Decimator downconverter, and a BFD/Mone from my Archer sled. Obviously the standard LCD was being powered as well. Power was coming from an IDX Endura 10.

 

Everything was quite happy, unless the focus puller made a rapid change in focus, at which point the whole sled would trip out. Cycling the sled power switch brought everything back up, but obviously it was pretty annoying due the RED bootup time.

 

A similar effect happened when I was a little over zealous in calibrating the focus stops and the M-one came up on the hard stop on the lens - everything tripped out.

 

The obvious answer is that in these two situations the BFD / M-one drew a little more power than under 'normal' conditions, and this tripped some sort of MCB or something in the sled that is reset by cycling the sled power switch.

 

The other option is that there was something faulty with the BFD / M-one, but I use this set all the time and haven't encounter this before.

 

What would be the best way to prevent this in the future? I can now understand why the more expensive rigs have multiple power supplies so you can power the camera separately to the AKS, but that's not an option on the Archer. Well, I *could* power the RED off its own batteries but the typical RED setups I work with are difficult enough to balance on the Archer without adding yet more weight above the gimbal.

 

Your thoughts appreciated.

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Hey Ed, how’s you?

 

I had the same issue like 3 years ago when I had my Archer. I was powering a Varicam, BFD and down converter shizzle, and on the fast focus pulls the whole thing started tripping out.

Never got to the root of it. I had a feeling it could be due to the size of the power lines inside the sled, veeeeeeeeeeeeery tiny. Didn't have any trouble after I modded that sled and used thicker wires.

To my knowledge, there was never any trip switches, manual or auto in the Archer sled.

We powered it off it's own onboard in the end and continued.

Could also be the batteries reaching maximum current output, and tripping to save the cells.

 

Rick.

 

 

Hi guys,

 

The other day a strange thing was happening. I was powering a RED, a Decimator downconverter, and a BFD/Mone from my Archer sled. Obviously the standard LCD was being powered as well. Power was coming from an IDX Endura 10.

 

Everything was quite happy, unless the focus puller made a rapid change in focus, at which point the whole sled would trip out. Cycling the sled power switch brought everything back up, but obviously it was pretty annoying due the RED bootup time.

 

A similar effect happened when I was a little over zealous in calibrating the focus stops and the M-one came up on the hard stop on the lens - everything tripped out.

 

The obvious answer is that in these two situations the BFD / M-one drew a little more power than under 'normal' conditions, and this tripped some sort of MCB or something in the sled that is reset by cycling the sled power switch.

 

The other option is that there was something faulty with the BFD / M-one, but I use this set all the time and haven't encounter this before.

 

What would be the best way to prevent this in the future? I can now understand why the more expensive rigs have multiple power supplies so you can power the camera separately to the AKS, but that's not an option on the Archer. Well, I *could* power the RED off its own batteries but the typical RED setups I work with are difficult enough to balance on the Archer without adding yet more weight above the gimbal.

 

Your thoughts appreciated.

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Hey Ed, how’s you?

 

I had the same issue like 3 years ago when I had my Archer. I was powering a Varicam, BFD and down converter shizzle, and on the fast focus pulls the whole thing started tripping out.

Never got to the root of it. I had a feeling it could be due to the size of the power lines inside the sled, veeeeeeeeeeeeery tiny. Didn't have any trouble after I modded that sled and used thicker wires.

To my knowledge, there was never any trip switches, manual or auto in the Archer sled.

We powered it off it's own onboard in the end and continued.

Could also be the batteries reaching maximum current output, and tripping to save the cells.

 

Rick.

 

Hey Rick! Thanks for the tip - the wire gauge does sound like it could be the culprit. When I'm feeling brave I might Have At the sled with a set of allen keys and a coathanger, see if I can poke a few new power leads down the post.

 

Are you about for the Broadcast Show in Earl's Court next week? Looks like I'll be on the Tiffen stand for a fair bit, would be good to say hi.

 

Cheers,

 

E

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Hi Ed:

 

BFD Master Jim can give you the details on current draw but I ran into a few situations before getting my Preston system that if I hit the stops on a lens with the M-One motors and was powering a bunch of other "schizzle" as you called it, I would blow a fuse on my Clipper 24. After a consult with Robert Orf at Tiffen we upped the fuse an amp or two and it took care of the problem without endangering the rig. You should inquire about your Archer before blindly following that method if you have an option.

 

In a few other scenarios I've lost power momentarily but then it would come back within a minute or so. It was not a blown fuse. Of course you can't duplicate the problem unless you're :60 seconds out from the opening shot on a live broadcast ;-}. What Robert suggested that might have been happening was the thermal overload on the IDX 10's was kicking in. I don't remember if that was happening with my PowerCubes or not. Nor did it make much sense since the camera power was via Triax and/or Fiber.

 

This probably didn't help a whole lot but I definitely have experienced those two scenarios.

 

Good luck with it!

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Hey Ed, yes, I think I am at the show Wednesday, possibly. Maybe catch you there?

 

If you do get to the stage of wanting to upgrade the wiring on the sled, it’s relatively easy to do. There are two screw terminals on the board in the top stage that take +12v and GND wires.

The coiled cable from your battery plate is the same cable that runs up the post, there is no junction. You have to take the post / top stage off, cut the original power wires (point of no return (beware of the coax in that bundle too)) unscrew, pull through and out. Wire up the new battery plate. Could probably get .75 speaker flex up there, if not the 1.5, but that depends if the hole in the base / back of battery will accept it. I know the top stage end will take 1.5.

Ultimately, you loose that lovely coil bit, but you have beefed up the wiring.

 

Good chance it’s the battery tripping tho…

 

Rick.

 

Hi Ed:

 

BFD Master Jim can give you the details on current draw but I ran into a few situations before getting my Preston system that if I hit the stops on a lens with the M-One motors and was powering a bunch of other "schizzle" as you called it, I would blow a fuse on my Clipper 24. After a consult with Robert Orf at Tiffen we upped the fuse an amp or two and it took care of the problem without endangering the rig. You should inquire about your Archer before blindly following that method if you have an option.

 

In a few other scenarios I've lost power momentarily but then it would come back within a minute or so. It was not a blown fuse. Of course you can't duplicate the problem unless you're :60 seconds out from the opening shot on a live broadcast ;-}. What Robert suggested that might have been happening was the thermal overload on the IDX 10's was kicking in. I don't remember if that was happening with my PowerCubes or not. Nor did it make much sense since the camera power was via Triax and/or Fiber.

 

This probably didn't help a whole lot but I definitely have experienced those two scenarios.

 

Good luck with it!

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Hey Ed, yes, I think I am at the show Wednesday, possibly. Maybe catch you there?

 

Yep should be; I'll be the one looking like he needs a haircut with the thick rimmed glasses. Thanks for tips for rewiring the sled power - I might take the top stage apart "just to have a look" and see what I think. What were the effects of not having a coily coily power lead in the post for you when changing post lengths? Was it a massive pain?

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I'm using a 2 stage 2" post now with my MK-V. I made a correctly gauged custom cable for that, and I've attached an image. I made it curl myself, I’m sure you could do the same...

 

Rick.

 

 

Hey Ed, yes, I think I am at the show Wednesday, possibly. Maybe catch you there?

 

Yep should be; I'll be the one looking like he needs a haircut with the thick rimmed glasses. Thanks for tips for rewiring the sled power - I might take the top stage apart "just to have a look" and see what I think. What were the effects of not having a coily coily power lead in the post for you when changing post lengths? Was it a massive pain?

post-1015-1234569467_thumb.jpg

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If the battery plate on the archer has a P-Tap connector you could use it to wire up a second plate to parallel two batteries to see if it is a battery problem.

I do this on my rig to add a third battery sometime. Juts make sure you get the polarity right.

 

~Jess

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I'm using a 2 stage 2" post now with my MK-V. I made a correctly gauged custom cable for that, and I've attached an image. I made it curl myself, I’m sure you could do the same...

 

Ah, nice work. Approve of the two colours :) And you say that's just 0.75 mm2 speaker cable?

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If the battery plate on the archer has a P-Tap connector you could use it to wire up a second plate to parallel two batteries to see if it is a battery problem.

 

That's a great idea. The E-10s have that feature where they will 'stack up' and do this for you, but it usually doesn't work for balance on the usual Archer backplate, so I've added another V-lock plate underneath the opposite end of the battery rails (which usually ends up almost directly under the post). I did that mainly as V-lock batteries are a convenient source of quickly-attachable mass, but now you've said that I'll definitely make up a P-tap to P-tap and parallel the two plates together. Lovely, thanks.

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Hi Ed

 

If it is tripping out the battery then the problem is with the battery and not the wiring. The fact that it is tripping the battery means that you must be drawing excess current up the post so the wiring must be capable of passing that much current.

 

One word, PowerCubes - or is that two words? If you can get the setup together again I will lend you one to do a test.

 

Robin

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That is 1.5 speaker cable in there. So like AWG 15 ish.

 

But like I said in my first post, and Robert and Robin also mentioned, It does look like it's the batteries tripping.

 

Rick.

 

p.s. There are 3 power lines in there and one 75Ohm miniature Video coax with solid core.

Unfortunately Speaker flex cores are only red and blue, so +12 and +24v are both red, and GND is Blue.

 

 

 

I'm using a 2 stage 2" post now with my MK-V. I made a correctly gauged custom cable for that, and I've attached an image. I made it curl myself, I’m sure you could do the same...

 

Ah, nice work. Approve of the two colours :) And you say that's just 0.75 mm2 speaker cable?

Edited by Richard J Lewis
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To my experience, the main reason is, sorry to say this, the abnormal amount of amperage the M1 motor draws, by default.

 

The same thing happens when powering through the 11pin or other connector on an Arri 435 or others. The electronics in the camera limits the maximum draw and the combination with the M1 is often too much, resulting in either irregular behavior of the controller (bartech in our cases) and/or shutdown from the camera.

 

We see none of these problems with Heden motors, which are only marginally less powerful.

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