RunRyder RC
 7  Topic Subscribe
WATCH
 2 pages [ <<    <    ( 1 )     2     NEXT    >> ] 1037 views POST REPLY
Scorpion Power Scorpion Power
HelicopterMain Discussion › DPS-1200FBa power supply issue
03-13-2016 04:49 AM  19 months agoPost 1
benco_heli

rrNovice

tallahassee, fl. 32303

My Posts: All  Forum  Topic

Trying to setup. Completed mods checked output at 12.3v for both. Then floated the board in one and checked output at 12.3v. Then connected negative from grounded board to positive of floated board. Only 12.3v output. Floated board shut off and won't come back on. Using a new unit I completed the mods and checked output of new unit at 12.3v. Being sure to keep units separate I connected the positive side of the original unit to the negative side of the new unit. Both power up then one goes off. The voltage starts to rise and gets to about 14v and then one unit shuts off. What am I doing wrong? Any help is greatly appreciated.

Cheers
Travis

PM  EMAIL  GALLERY  Attn:RR  Quote
03-13-2016 05:45 AM  19 months agoPost 2
ticedoff8

rrKey Veteran

Morgan Hill, CA. USA

My Posts: All  Forum  Topic

I assume you used this thread:
http://www.rchelination.com/setting...b-power-supply/

And, you measured the resistance from the chassis to the neg lead on the "floated" power supply, and it was open?

Personally, I only use Dell power supplies. They are much easier to convert

Believe 1/2 of what you see and none of what you hear.
Fake News will be the downfall of our Republic!

PM  EMAIL  GALLERY  Attn:RR  Quote
03-13-2016 02:00 PM  19 months agoPost 3
Baane

rrNovice

Huntsville, Al

My Posts: All  Forum  Topic

It doesn't matter sometimes, but it might matter on this PS. You wired it in the wrong sequence. According to your post: "Then connected negative from grounded board to positive of floated board."

You should have the unmodified supply as the low side voltage. This ensures that the negative terminal on the unmodified supply is at zero volts and the negative on the floated supply is at ~12 volts. It can cause a problem if the dc ground is not isolated from the ac side ground.

"10. Now, to connect the floating supply in series with another supply, connect the positive terminal on the grounded 12V supply to the negative terminal on the floating 12V supply."

Huntsville Heli Flyers

PM  EMAIL  GALLERY  Attn:RR  Quote
03-13-2016 02:10 PM  19 months agoPost 4
benco_heli

rrNovice

tallahassee, fl. 32303

My Posts: All  Forum  Topic

Yes I realized that after the fact. But would the way I connected the supplies in series damage the floated unit? Also, I if neither unit is floated then it shouldn't make any difference, right? At this point I want to get 25.4v without floating one of the boards to verify I have everything correct. But I am unable to get the series output

PM  EMAIL  GALLERY  Attn:RR  Quote
03-13-2016 03:11 PM  19 months agoPost 5
jschenck

rrProfessor

La Vista, NE.

My Posts: All  Forum  Topic

I'm pretty sure if you connect the DC pos of one chassis to the DC neg of the other you'll create a dead short through the common AC ground that both chassis share. That's why you have to float the DC ground on one.

Sorry, I can't help with why one is shutting down after you float the ground beyond the two suggestions already given:
1. voltmeter to make sure the floated PS has no DC ground to the chassis
2. connect up the AC grounded NEG to the AC floated POS

PM  EMAIL  GALLERY  Attn:RR  Quote
03-13-2016 03:28 PM  19 months agoPost 6
rcnut

rrElite Veteran

Rockford, Illinois

My Posts: All  Forum  Topic

I disconnected "both" AC ground wires. Then I used packing tape to cover the chassis so they won't short out. These power supplies are designed to shut down (fold back) when the output is shorted...a way of protecting the supplies.

Team Miniature Aircraft
"I love the smell of Nitro in the morning!"
...Citizen 654!

PM  EMAIL  GALLERY  Attn:RR  Quote
03-13-2016 10:14 PM  19 months agoPost 7
benco_heli

rrNovice

tallahassee, fl. 32303

My Posts: All  Forum  Topic

Rcnut

When they shut down how are they reset? The one I floated shut down and has never worked again.

PM  EMAIL  GALLERY  Attn:RR  Quote
03-13-2016 10:20 PM  19 months agoPost 8
benco_heli

rrNovice

tallahassee, fl. 32303

My Posts: All  Forum  Topic

Jschenck

It makes sense that if they are using the same ground on the output side that it will create a short. My friend (extensively experience heli pilot) uses the same model without floating the board and it works fine. Just a little confused. I'll try floating the board, check output and grounding and give it another shot. I just hope I don't fry another unit.

PM  EMAIL  GALLERY  Attn:RR  Quote
03-14-2016 08:03 AM  19 months agoPost 9
ticedoff8

rrKey Veteran

Morgan Hill, CA. USA

My Posts: All  Forum  Topic

I float both power supply's cases from the negative output
You didn't hurt the grounded PS by connecting it.
It should still power up with no problems.

But, I would NEVER float the AC ground
The AC ground lead should definitely be grounded to the case.
But, if you followed the direction, the AC ground and the chassis ground will not be connected to the negative lead.

Believe 1/2 of what you see and none of what you hear.
Fake News will be the downfall of our Republic!

PM  EMAIL  GALLERY  Attn:RR  Quote
03-14-2016 11:20 AM  19 months agoPost 10
EEngineer

rrProfessor

TX

My Posts: All  Forum  Topic

floated the board
What does this mean?

FWIW

Logo 600SXs, 700XX, 800XX

PM  EMAIL  GALLERY  Attn:RR  Quote
03-14-2016 02:29 PM  19 months agoPost 11
jschenck

rrProfessor

La Vista, NE.

My Posts: All  Forum  Topic

floated the board
What does this mean?
The mounting bolts for the PCB's are metal - the common ground of the PCB is exposed on the mounting holes. To float the DC ground you replace the bolts with plastic hardware to islate the PCB ground from the chassis.

A little schooling for EE from a non-EE

PM  EMAIL  GALLERY  Attn:RR  Quote
03-14-2016 04:30 PM  19 months agoPost 12
rcnut

rrElite Veteran

Rockford, Illinois

My Posts: All  Forum  Topic

Rcnut
When they shut down how are they reset? The one I floated shut down and has never worked again.
Resetting the supply that "folded back" on itself (aka shut down), is unplugging the AC power to the supply and let it sit for a minute or two. There will be some residual power within the supply (by electrolytic capacitors) still charged up. You are waiting long enough for the protection circuit to reset.

Team Miniature Aircraft
"I love the smell of Nitro in the morning!"
...Citizen 654!

PM  EMAIL  GALLERY  Attn:RR  Quote
03-14-2016 07:32 PM  19 months agoPost 13
benco_heli

rrNovice

tallahassee, fl. 32303

My Posts: All  Forum  Topic

I have waited several days and still doesn't come back on. I'm wondering if it has something to do with the fact that I floated both the output and the main circuit boards. In the instructions it's says to replace all three screws with nylon. In the comments someone mentions that the main circuit board does not need to be isolated Maybe the main board needs the ground in order to verify there is no longer a short.

PM  EMAIL  GALLERY  Attn:RR  Quote
03-15-2016 03:14 AM  19 months agoPost 14
benco_heli

rrNovice

tallahassee, fl. 32303

My Posts: All  Forum  Topic

Floated the new unit and successfully was able to run in series. Although I'm only getting 18v. When I test each individually the new unit is producing 10v and the original non floated is putting out 12.3v. I tried adjusting the pot as described in the instruction but nothing changes

PM  EMAIL  GALLERY  Attn:RR  Quote
03-15-2016 10:32 PM  19 months agoPost 15
ticedoff8

rrKey Veteran

Morgan Hill, CA. USA

My Posts: All  Forum  Topic

As I read through this, I would suggest that the OP make sure their life insurance is paid and up to date.

There are too many red flags in this thread.

Believe 1/2 of what you see and none of what you hear.
Fake News will be the downfall of our Republic!

PM  EMAIL  GALLERY  Attn:RR  Quote
03-16-2016 12:23 AM  19 months agoPost 16
benco_heli

rrNovice

tallahassee, fl. 32303

My Posts: All  Forum  Topic

I have everything working perfect. A big thanks to those of you that contributed helpful information.

PM  EMAIL  GALLERY  Attn:RR  Quote
03-16-2016 05:17 PM  19 months agoPost 17
AirWolfRC

rrProfessor

42½ N, 83½ W

My Posts: All  Forum  Topic

You say
Although I'm only getting 18v.
Than you say

I have everything working perfect.
So what bit of magic happened to do that ?

PS
I usually check the input of the power supply to see if the hot and neutral are going directly to an isolation/step down transformer and not connected to chassis ground and then lift the ground line from the power cord. Then I have my "floated" supply. Just keep the chassis isolated from the other chassis.

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
03-16-2016 06:17 PM  19 months agoPost 18
benco_heli

rrNovice

tallahassee, fl. 32303

My Posts: All  Forum  Topic

Not exactly sure what changed because I just came back the next day powered everything up and wala 25v. Possibly my v-meter needs a new battery. The units are mounted together and everything is good. Again thanks for the help guys.

PM  EMAIL  GALLERY  Attn:RR  Quote
03-16-2016 06:23 PM  19 months agoPost 19
benco_heli

rrNovice

tallahassee, fl. 32303

My Posts: All  Forum  Topic

Ticedoff8

It would probably more helpful if you could elaborate on these red flags you see. I'm okay with a little constructive criticism.

PM  EMAIL  GALLERY  Attn:RR  Quote
03-16-2016 06:35 PM  19 months agoPost 20
AirWolfRC

rrProfessor

42½ N, 83½ W

My Posts: All  Forum  Topic

The main problem with putting two power supplies in series is that most all power supplies have DC negative, chassis and AC ground tied together for safety reasons. If you connect the negative of power supply A to the positive of power supply B, you have effectively shorted out power supply B. The short goes through the ground on the AC plug.

As I noted earlier, you need to isolate the negative of one of the power supplies to make it's output "float" (no ground connection). Then you can use it in series with an unmodified supply.

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
WATCH
 2 pages [ <<    <    ( 1 )     2     NEXT    >> ] 1037 views POST REPLY
Scorpion Power Scorpion Power
HelicopterMain Discussion › DPS-1200FBa power supply issue
 Print TOPIC  Make Suggestion 

 7  Topic Subscribe

Monday, October 23 - 9:58 pm - Copyright © 2000-2017 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online