Safety Link/ Links

[froggy]

Hi Guys

For my latest creation i will be using 2 voltage power rails 12v and 24v (see profile pic)
Where would best place to put safety link /links ?

Cheers Froggy

[john_frizell]

Safety Link/ Links

The circuit as drawn on your profile will not provide 24 volts where it says 24 V. Also you have batteries in parallel. If they are nicads you need to be sure they are at the same state of charge before connecting them in parallel. Dont try to charge them in parallel.

[woody]

Safety Link/ Links

Sticking a wire between the neg of M1 and the pos of M2 should ........ I think .... give you 24v on M3.

[froggy]

Safety Link/ Links

Thanks for response guys...oops i missed a wire !!! new pic on profile...still cant work out best place for safety link/links ??

[woody]

Safety Link/ Links

I think that youll need 2 ... doubled up to make a single link.

One link in each off the top lines of your drawing and before the speedos ........I.E. Just before the + shown in your drawing and just before the - shown in your drawing.

[froggy]

Safety Link/ Links

Hi Alan and all

I think between us we have come up with the best solution ! (see profile pic) comments and recomendations welcome .

Cheers Froggy

[woody]

Safety Link/ Links

Yup ...that should do it.

[geoff]

Safety Link/ Links

Agreed, that covers all the requirements of the removable link rule. Dont forget your power light... wire a 24v LED across the downstream sides of the links or across the item marked as 30A speed controller on your diagram.

[grant_ploughbot]

Safety Link/ Links

his power light has been put in the diagram by the link!

[mark_m]

Safety Link/ Links

Slightly OT but are you going to optoisolate your ESCs from your receiver? (Isnt the signal ground normally connected to the supply ground for ESCs, creating a ground loop?)

[froggy]

Safety Link/ Links

Whoaaa !!!!!(recommendation goes over my head )!!!

As long as the bloody thing works i will be happy..As many of you that have seen my bots..they always look good but never work properly.

Cheers Froggy

[mark_m]

Safety Link/ Links

Depending on how your speed controllers are wired internally, you might end up letting the magic smoke out!

The negative supply of M1s speed controller is 12V higher than the negative supply of M2s speed controller. If the black wire that goes from your speed controllers to your receiver is also connected (internally) to the negative supply to the speed controller then both negative supplies will be connected together, via the receiver.

If the black wire isnt connected to the negative input then you dont have a problem, but if it is, somthing will have to give, probably a pcb track in one of your speed coontrollers. I thought you might want warning :-)

Ill check my electronizes later when I get home to see if they have signal ground connected to their negative supply but I think the IFI victors have them connected and some other ESCs do.(http://forums.delphiforums.com/n/mb/message.asp?webtag=THERFL&msg=3706.8&search=yhttp://forums.delphiforums.com/n/mb/...3706.8&search= y)


Hope this helps

[froggy]

Safety Link/ Links

Hi Mark

Thanks for warning info....I will be using standard 15a elecronize speed controlers in this bot so look forward to hearing your findings.

Cheers Froggy

[mark_m]

Safety Link/ Links

Ive just checked my 30Amp electronizes and the negative supply from the battery to the speed controller is connected to the black wire to the receiver.

Assuming your 15A ESC and 30A ESC in your wiring diagram are all electronizes, I think you might have a problem.

Possible solutions (off the top of my head, might not be practical):
1. Use an optoisolator between the receiver and the ESC.
2. Modify the ESC pcb to remove the connection
3. control the ESC using a mechanical connection (servo driving a pot or similar)
4. use two receivers (electricaly isolated)
5. use relays instead of ESCs
6. use ESCs that are already isolated.

Simplest solution is probably to get an optoisolator. The only ready made solution for RC I can find is the zero glitch module (£8.99) sold here: http://www.goldstarstockists.com/tamiyaparts/tpx/electronicgadgets.htmhttp://www.goldstarstockists.com/tam...nicgadgets.htm
I wouldnt have thought its too hard to build your own using a cheap IC though. Somebody else whos had a go at this could probably chip in with some advice here.

[froggy]

Safety Link/ Links

Hi Mark

Well it did look good on paper !!!!

1) Use an optoisolator between the receiver and the ESC. .....£9.00 for each ESC....£36 total...
2)Modify the ESC pcb to remove the connection ..then would have to have seperate bat pack for rx
3)not practicle
4) same as 2)
5) this is for a high speed spinner bot so need all control i can get
6) got to use what ive already got

Might be cheaper and easier to run 24v gold as opposed to 12v drill motors....or run drill motors at 24v and smell the smoke !!!

Cheers Froggy