What am I doing wrong now

[Andy CParticipant @andyc56856]

hi everyone

I have recently bought a new little brushed motor and a set of suppressors. Easy I thought, even read the instructions that came with them and did a search here for any other useful information. Found an interesting discussion started a long time ago about whether they are needed or not. Not opening that can of worms again. Just going to fit them.

Armed with some sandpaper to roughen the surface, some solder and my trusty iron, off I went on a journey to not working and back again.

So, not to be deterred I grabbed a great big rasp from the tool box and roughened it a bit more. Hotel not working for an overnight stay. After a big breakfast of "I am not going to give up" I grabbed some different solder, fired up the gas torch and tried again. This trip is seriously bugging my melon man.

So what the heck is going wrong? Wrong solder, still not rough enough or something else entirely?

To save on trips to "this is still not working" I submit myself to your thoughts.

Cheers

Andy

[Andy CParticipant @andyc56856]

[Paul TParticipant @pault84577]

Hi Andy

Sounds like the can isn't getting hot enough for the solder to stick or the metal isn't clean enough for the solder to stick.

I use the tip of the iron to pre heat the area before trying to solder and I use plumbers flux to keep the metal from oxidising when soldering a tag onto a can.

Paul

[Dodgy Geezer 1Participant @dodgygeezer1]

I swear by plumber's 'Active' flux, which is an acidic compound. With it, you don't even have to clean most copper surfaces, and it seems to make solder stick to most metals…

[Andy CParticipant @andyc56856]

Cheers. I will look that up and try again

Andy

[Colin BishopModerator @colinbishop34627]

Paul is probably right, the can isn't getting hot enough but if you do manage to apply enough heat you might damage the motor, especially if the end plates are nylon or have nylon bearings.

Do the suppressors need to attach directly to the can? Usually it is sufficient to simply bridge the supply terminals. If you must attach to the can then many motors will have mounting screw holes on the front face and you can simply make a tag mechanical connection to one of those using a small (and short!) screw.

Colin

[Malcolm FraryParticipant @malcolmfrary95515]

a) there is a thin chance that the metal won't solder.

b) I have yet to need anything other than a single capacitor across the terminals. On small motors with tags with holes in, I poke the capacitor legs through and solder them, then use the excess wire as a more useful tag.

Apart from using the right flux and tinning, the trick is a big enough hot enough iron to get the metal hot enough quickly enough that the heat doesn't have time to travel to areas where damage will occur. My basic reason for not doing it.

As an aside, if one of the "side" capacitors goes disconnected there is a strong-ish theory that any interference, rather than cancelling, will enhance due to the imbalance created.

[Andy CParticipant @andyc56856]

Okay, I have soldered the on across the terminals. I will try again and if no success I will leave it at the one. It was just that the instructions said to install the three. I will also investigate if I can add tags to the can with screws too.

Thanks for the help.

While I have you though, could I ask one more.

I am putting a car windscreen pump in one of Ashley's LCMs. The set up is an action speed controller, main board and switch. I have a great diagram from Mr Milbourn and it all works great by using a spare channel to operate the pump. However I have a twin outlet pump, thinking it would squirt water through both outlets at the same time. Ha ha, no only one side squirts. So he other side must be switched differently in a car. Can it be set up to do this in the boat. I.e. Left stick left fires one outlet, left stick right fires the other. Works okay with one and a splitter, but two independent would be awesome.

Cheers

Andy

[BanjomanParticipant @banjoman]

Andy,

I have had similar problems with unseuccesful soldering direct to the motor can, but happened to read somewhere or other that if such were the case, a work-around would be to take a strip of thin copper sheet, wrap that around the can, simply put the capacitor legs under the strip and secure the whole thing with a small screw-and-nut through the ends of the strip.

As the below photo shows, I then also used the strip to earth the can to the propeller shaft …

Mattias

Edited By Banjoman on 29/07/2017 21:24:49

[ashley needhamParticipant @ashleyneedham69188]

Like Malcolm, the motors with just one capacitor across the terminals have given no problems. I have in the past struggled and soldered capacitors to the can but don't bother any more.

I would try just one capacitor and in the unlikely event you get interference, do as Colin suggests. The propshaft tag is also a good and easy idea. In the case of the above, a wire around one of the mounting screws would do

​OR use a brushless motor….job done.

​Ashley

[Malcolm FraryParticipant @malcolmfrary95515]

I am putting a car windscreen pump in one of Ashley's LCMs. The set up is an action speed controller, main board and switch. I have a great diagram from Mr Milbourn and it all works great by using a spare channel to operate the pump. However I have a twin outlet pump, thinking it would squirt water through both outlets at the same time. Ha ha, no only one side squirts. So he other side must be switched differently in a car. Can it be set up to do this in the boat. I.e. Left stick left fires one outlet, left stick right fires the other. Works okay with one and a splitter, but two independent would be awesome.

That depends on the particular details of the pump and the wiring of the car it was intended for. I can imagine lots of ways of doing it, but probably all wrong, depending on the pump. Most screen pumps are a centrifugal impeller in a chamber, whichever way they turn water in the middle is thrown outwards, its only escape is through a hole in the side, and off up the pipe.

[ashley needhamParticipant @ashleyneedham69188]

There are only two "outlets"??? or is one in and one out???

​Centrifugal pumps….now there's a thing

Ashley

[Colin BishopModerator @colinbishop34627]

I've seen this problem described before. I suspect one outlet is for the front screen and one for the back. I don't know how the internals work but maybe if you reverse the voltage the water will come out of the other outlet then you know what needs to be done!

Colin

[Malcolm FraryParticipant @malcolmfrary95515]

That's a thought. If the chamber where the impeller lives is shaped that way, then water flung out sideways will also try to travel in the direction of rotation, so one outlet will be favoured over the other depending on the direction.

The few that I have taken apart (singles only) have all had what looks like a paddle wheel in there on the motor shaft, with an inlet hole in the middle and an outlet to one side. Now trying to remember if I have ever washed both front and back screens at the same time. Obviously not possible with a single pump that runs in reverse for the rear screen.

The paddle wheel in a bow thruster is configured so that it sits sideways, with only the bottom half in a tube, so that water gets pushed one way or the other rather than a single inlet and two outlets.

[Colin BishopModerator @colinbishop34627]

There may be some simple flap valves incorporated. Vehicle manufacturers are experts at going to the simplest and cheapest solutions.

Colin

[Andy CParticipant @andyc56856]

Thanks chaps

Looks like I have some testing to do. I will check which side the water comes out of depending on the polarity of the wires and let you know.

Andy

[TelstarParticipant @telstar]

Hi Andy

There is normally two types of windscreen washer pump used on cars, one is a centrifugal, as Malcolm explained,

the other is a spur gear pump. There are pros. and cons. For both types.

The spur gear pump has inlet and outlet symmetrical, and will pump either way by reversing the motor.

Centrifugal pumps have inlet in the middle and outlet from the side, these only work correctly in one direction.

The images are typical but not absolute

Cheers Tom

[Colin BishopModerator @colinbishop34627]

The pump referred to has twin outlets so it probably works like this:

**LINK**

So, as I suggested earlier, reversing the polarity switches between the two outlets. OK for a bow thruster but not a fire hose!

Colin

[Glynn GuestParticipant @glynnguest59245]

Andy C,

If the pump is as you describe, i.e. a single inlet but two outlets, it's probably the same as I used in the Elliot fireboat (Oct 2011 issue).

Due to the swirling action of the centrifugal impeller, water is driven into one outlet or the other without the need for any fancy valves or such like. This was ideal for this model since a simple servo operated reversing switch (no need for anything electronic) would operate either the twin fixed monitors or the monitor on the elevating/rotating platform.

Hope this helps.

Glynn Guest

[Andy CParticipant @andyc56856]

Hi everyone

Thanks for all the comments. The motor is indeed a centrifugal pump. Single large inlet and two identical (although different colours) outlet. I have taken a photo and the pump can be seen at the top of the picture.

So to test out the theory I did a couple of tests. After checking which outlet the water comes out from, in the first instance White, I swapped the leads over. Guess what, water then comes out of the black one. Yipee. So what next. I like Glynn's idea of a simple ( I like Simple) servo reversing switch. So tomorrow I will look one up and see what it is and whether it will be easy to wire in.

Below is a pic of the electrics board in the hull and a wiring diagram kindly supplied by Dave M.

Pretty sure I can work it out, but I will ask if I get stuck.

Cheers

Andy

[Andy CParticipant @andyc56856]

Okay, now I am stumped. I have had a look around the net and can find lots of articles and forum posts for actually reversing a servo, via dismantling it and use of y leads and such. Also a plug in thing that reverses the servo too. But none the wiser on the gadget Glynn was talking about. Could I use another Action P91 and somehow wire that in and use another channel. If so how?

Cheers

Andy

[NoelParticipant @noel26080]

Don't you just need a double-pole-double-throw switch cross-wired to reverse the pump motor:

and then have that switch flicked to either position by a servo?

[Dave MilbournParticipant @davemilbourn48782]

That'll do the job as long as it's a "3-position centre=off" type and of sufficient rating for the current drawn while the pump is operating. If you want a more elegant solution then the ACTion P44 Twin Relay switch should do the job, with both relays capable of 3A continuous current. The relays switch at about 40% of full stick movement either way and can be set to be non-latching or latching by use of a little on-board DIL switch. See the diagram "Driving one motor in both directions" on page 2 here **LINK**

Dave M

[Andy CParticipant @andyc56856]

Posted by Dave Milbourn on 03/08/2017 17:28:57:

That'll do the job as long as it's a "3-position centre=off" type and of sufficient rating for the current drawn while the pump is operating. If you want a more elegant solution then the ACTion P44 Twin Relay switch should do the job, with both relays capable of 3A continuous current. The relays switch at about 40% of full stick movement either way and can be set to be non-latching or latching by use of a little on-board DIL switch. See the diagram "Driving one motor in both directions" on page 2 here **LINK**

Dave M

thanks Dave

So that would replace the P91 and when used on say left stick left/right (not sure what that is called) it would fire relay 1 when pushed left and 2 when pushed right?

[Andy CParticipant @andyc56856]

Thinking ahead. If I bought the Quadswitch, I could power on some lights and something else too.

Andy

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