Model Boat Mayhem
Technical, Techniques, Hints, and Tips => The "Black Arts!" ( Electrics & Electronics ) => Topic started by: dickyp on November 02, 2011, 02:51:47 pm
-
My local model shop has sold me a microswitch to operate my fast speedboat rather than use a speed controller
Could uo please advise where he NC, NO and common are wired to
Thanks
-
I think we need a little more information on the boat and it's electrics. Perhaps a picture or two.
All I can comment on is the switch and the meanings of your abbreviations.
N.O means normally open
N.C means normally closed
Common is the centre connection which either joins to one of the above, depending on where it's switched.
I assume you are choosing whether to go forward or backward ? I would have thought it was nicer to have a speed controller however.
Hope this helps
Ken
-
All you will have with a servo actuated microswitch is 'all or nothing'
i.e. flat out or stop.
The switch needs to be fitted in the motor feed one lead to common from the battery and then on to the motor from
NO.
When the switch is made the motor will run.
One thing you must check is that the power rating of the microswitch is above the power drawn by the motor on load
Ned
-
You may find depending how youve set things up a delay before the motor stops as the servo has to move to break the contacts.Most microswitches have a very low amperage swiching capacity say 500ma. So are only suitable for very small motors. John.
-
One thing you must check is that the power rating of the microswitch is above the power drawn by the motor on load
Ned
No problem to find microswitches capable of 10A or more at 250V. I think even Maplin might sell them %), Squires certainly do.
Barrie
-
Take a lead from the positive (red) side of the battery to the N.O. terminal and then a lead from C or common to the positive side of the motor.
Adjust switch / servo mounting so the servo operates the switch without stalling.
Lots of people used to run switched fast electrics rather than a speed controller because they were always flat out anyway.
Ratings up to 10 to 15 amps quite common - and so cheap, when they stop working just replace them...if you have issues getting a suitable one let me know.
-
if you were to use 2 microswitches in paralel wiring would this overcome limited current issues?
-
That's a possible way round it and it might mean the difference of getting back to shore or being stuck in the middle of the pond!
A lot of micro switches can take a lot more than they are rated for - it's usually the actual making and breaking of the contacts that causes the arcing that burns them out quicker.
I have run a couple of 'switched' boats in the past - one used a microswitch for on/off and a couple of switches as a parallel / series switch for two 6 cell nicad packs to give me off / 7.2v / 14.4v - the 540 motor on a 2:1 gearbox ran very well with a x45 prop.
The other was a 16" Atlantic Streaker 540 motor, 6cells and an x30 prop. - never an issue until it hit the pond wall and sank.
-
if you were to use 2 microswitches in paralel wiring would this overcome limited current issues?
Only if you can synchronize them precisely. If there is only a few microseconds difference between the making/breaking points, one of the contacts will suffer a lot more than the other, and die early. This will then overload its mate and kill that, too.
The "micro" in the name refers to the switching time rather than size or current switching/carrying capability, but if using them, make sure that if the current is more than a small fraction (10%) of the rated current to fit a spark quench circuit across the contacts. Watching the operation of one of these things on a scope looks like a round of applause due to contact bounce. The release is just a one-shot event, however.
-
dicky p why did the shop sell you a micro switch?? you still need a servo of course and if thats the case why not use a mechanical speed controller? i presume your receiver has a safety cut off if you lose signal otherwise your boats not going to stop if u do :o
-
Thanks for your responses
My boat is very light and travels very fast.
Their comments were that the boat is meant to be used on full power so why use a speed controller
It is 17" long and 7" beam
I think the concensus is that I should use a controller
(http://s7.postimage.org/3qso0l60n/03112011054.jpg) (http://postimage.org/image/3qso0l60n/)
-
Back in the elder days, controllers tended to be big, heavy things, and even the best ESCs lost significant power. Nowadays, there are forward only ESCs that actually weigh less than the servo that would otherwise be needed, and can handle considerably more current than most microswitches. They also, with a bit of shopping around, probably cost less than a servo and switch. Only caveat there is, if its oriental, take their amp figure, remove a zero, think of a number and divide by that, and you will be about right for continuous use in a boat. Most of these ESCs were intended for flyboys, and these invariably have lots of moving air to cool them, not so inside a hull.
A fast boat is considerably less resilient than a concrete bank, so proportional control is better than on/off when bringing the boat in.
Reverse, while not much use out on the water, can be useful if you manage to go aground or get into a tight corner.
-
Reminds me of the time back in the 50's when my Father made me Double O train set ( yes, he hand made the rails and bought a train with carriages). With no money left for anything 'controller wise' he provided an ON/Off switch.
Great fun driving it on Xmas day. You had to switch off when approaching corners to allow it to skid around, before restoring power for a flat out run down the straight. You needed a ESC in your head. :}
ken
-
Ref original question:
1. Obtain 800mm of 7/0.2 multistrand plated hook-up wire
2. Strip approx 8mm of insulation from one end
3. Twist and tin with solder
4. Loop tinned wire through the hole in either the COM or N/O terminal of the microswitch and bend back along terminal
5. Apply iron and solder
6. Heatshrink the joint for insulation and physical support; allow to cool
7. Hold the other end of the wire between thumb and forefinger
8. Lower the switch into a opened wastebin, let go of the wire and close the lid
Welcome to the 21st century 8)
DM
-
{-) {-) {-)
-
use a speed controller dicky. my boat has a forward only 30 amp esc:
http://www.ebay.co.uk/itm/Turnigy-30A-30-AMP-BRUSHED-ESC-Speed-Controller-UK-/190593428516?pt=UK_ToysGames_RadioControlled_JN&hash=item2c6040ec24
the only draw back is with this is that its actually an aircraft esc. and only register stop as fully reverse on your controller. when i had a stick type 2 channel, i removed the centre return spring on the throttle, then pushed the stick all the way backwards. if the stick is not in this position when you start up the esc will beep saying the stick is not in neutral and wont start. When i ugraded to trigger type transmitter, i had modyfy that too so the trigger was fully forward.
-
Its a personal decision, but if buying an esc id definately get one with a reverse. You never know when you may get caught on something. Sods law your boat will just be out of reach and jammed so other boats cannot get to it .John.
-
hi what size motor are you using as i might have a speed controler for a small amount comperd to its new cost you could buy
-
Its a personal decision, but if buying an esc id definitely get one with a reverse. You never know when you may get caught on something. Sods law your boat will just be out of reach and jammed so other boats cannot get to it .John.
I would say that's almost guaranteed! O0
-
Ref original question:
1. Obtain 800mm of 7/0.2 multistrand plated hook-up wire
2. Strip approx 8mm of insulation from one end
3. Twist and tin with solder
4. Loop tinned wire through the hole in either the COM or N/O terminal of the microswitch and bend back along terminal
5. Apply iron and solder
6. Heatshrink the joint for insulation and physical support; allow to cool
7. Hold the other end of the wire between thumb and forefinger
8. Lower the switch into a opened wastebin, let go of the wire and close the lid
Welcome to the 21st century 8)
DM
Thank you for the clear and precise step by step instructions :-)) :-)) which I followed to a "T" but the switch doesn't work, what have I done wrong. %) %) %)
-
hi what size motor are you using as i might have a speed controler for a small amount comperd to its new cost you could buy
Thanks for the offer
I now have 2 of the Mtroniks controllers, one that I can't get to work and the other I daren't even open.
at the moment I am £60 out of pocket and hopefully, by the fact they have a good name, they will sort it for me
The motor I am using in my big boat is a Graupner 600 eco running (at sometime possibly) on 8.4 volts
-
Hi Arty, you should have taken the lid off the bin first, Mick B.
-
Mick B,
:-)) :-)) {-) {-)
-
I now have 2 of the Mtroniks controllers, one that I can't get to work and the other I daren't even open.
Hi Dicky,
Any chance you can take a picture and post so we can see how it's all wired up?
Uploading photo's:- http://www.modelboatmayhem.co.uk/forum/index.php?topic=23.0
Uploading photo's using an External host:- http://www.modelboatmayhem.co.uk/forum/index.php?topic=2277.0
-
Hi Martin
Abondoned micro switch and boat Mtroniks controller
Thanks for your help
-
if you were to use 2 micro switches in parallel wiring would this overcome limited current issues?
Just use the micro switch to power a relay ,use low current across the switch to fire a relay that will sustain the current ..If that's not possible ..just about any 12 or 24 volt surface mount starter solenoid will suffice..