homemade power trim relay

[PondTunes]

Re: homemade power trim relay

Wouldn't a 12.00 switch with a 12.00 switch protector plus 40-50 or more feet of 10 AWG wire (another 20 bucks) plus shipping, be more expensive than 2 $5.00 relays (with sockets + wire) and a $10.00 marine grade SPDT momentary switch?

You're going to need to run SIX 10 AWG wires from the back of the boat to the helm, One + & - from the battery to power the switch (20'?) then FOUR more to the trim unit (40'?)...

The diagram I posted also has the advantage of being triggered by a ground thus no need to put a fuse at the switch, no need to worry about the possibility of six wires getting chaffed on something.

 

[guy74]

Re: homemade power trim relay

One bad thing about just using a DPDT switch is it makes it more complicated to add extra switches to control the T&T (such as a transom or motor mounted switch). Also if you did use two switches you could short it out if both switches were pushed in oppisite directions at the same time. Could happen pretty easily. I have a motor mounted switch, great for putting the transom saver on.

 

[dsujen]

Re: homemade power trim relay

thanks for all the ideas. I like that motor control reversing relay the best.

 

[Texasmark]

Re: homemade power trim relay

Wire2, sir you are correct.

I am recalling relays I used to use that had several contact ratings and the rating depended upon the type load "to be interrupted" as you mentioned.

I've been trying to forget all that I had to know when I worked and looks like I'm doing a pretty good job of it. LOL.

Yea verily on the size of the clothes dryer wiring.

Also, that's the nice thing about using a remote controlled high current relay. You keep the high current wires short and just use signal wiring to control it. That has merit too......which I didn't think about.....forgot to remember. More LOL.

Also, running high current all the way to the switch makes for line drop which, if excessive, due to higher than expected current, or too small a wire, could keep the trim from working properly. Now I remembered that part.

Geez it's good to kick things around......keeps us honest and insures the reader gets accurate information.

Thanks,

Mark

 

[jtexas]

Re: homemade power trim relay

just for the record..........my diagram represents the dealer installation of my OMC power tilt unit in 1980 - simple & effective but as noted, other methods described here offer better safety and more flexibility for adding transom and/or bow switches.............actual results may vary...........

 

[wildmaninal]

Re: homemade power trim relay

Also if you did use two switches you could short it out if both switches were pushed in oppisite directions at the same time. Could happen pretty easily.

.

If you have a child in the boat maybe, or somebody mentally ill. I would hope that I would be the only person to tend to the switches in my boat. No offense intended. But I'm am happy with the way mine is setup, in my opinion. DPDT switch is a tilt/trim switch even recommended by the local marina.

 

[Texasmark]

Re: homemade power trim relay

Been thinking about this stupid switch all day (couldn 't plow cause it's too wet and can't cut hay cause thunderstorms are in the forcast; can't go fishing either for the same reason).

Here are a few observations.

1. The switch I suggested is rated for 3/4 hp. That means it is meant to turn on and off a 556w inductive load like for a motor to start your band saw or drill press type thing. Those aren't high current applications when you turn power on or shut power off.....pretty much idle current in both instances so the L di/dt kick is rather low. It's rated for 230VAC or 250VDC....sorta gives you a hint, with that hp rating and that voltage, that the contacts aren't going to be the size of a quarter. Contacts are probably good for 10 to 15 amperes as are most switches.....course locked rotor break current depends upon size, material, and gap, which were not stated in the catalog. It's probably intended to be used in the higher voltage circuits that will significantly reduce the current to reasonable levels. The terminals are bayonet (accept push on crimp terminals) which are usable to 20 amperes in other applications that I know of.

2. My PTT contains a 20 amp fuse and the PTT in my serv manual is good for Merc 3 and 4 cyl inline engines to 125hp. So I guess my trim current is in the order of 15 amperes including surges as it it a fast blow fuse; no time delay for starting surges and that should be adequate for dsu's 110 OMC.

3. Difference in PTT controls and a clothers dryer is that a dryer is designed to run continuously for about an hour. The heating elements may or may not be thermostatically controlled. PTT runs for a few seconds periodically. The heat load on the wiring is nearly non-existent so the line drop caused by hot copper is not there.

4. Therefore the wiring from the engine to a dash mounted switch would not be under that much stress so large gauge wires wouldn't be needed....like a pair of 10AWG ought to work for starters). On the flip side, with only 12V to work with, any line drop (including tenth's of a volt) would be a significant part of the available voltage and may influence operation, whereas a relay in the engine would not have much of a concern for line drop since the distance to the trim motor is so short.

5. The switch is a viable option over one relay as it can be reversed to get the necessary dual reversal of power to the motor, whereas relays are usually normally open and activation closes them......unidirectional operation only, which is why 2 are required. I realize you can get DPDT relays, but you need to interrupt power for "Trim Off" function and so you need the extra contacts that you don't need with the ON-Off-ON DPDT switch since the DPDT relay is ON-ON.

Well I hope we all gleaned something from this. I say that I want to forget what I have had to do when working but not really. It's good to run the brain thru the traps periodically. One reason I visit this site....keep the brain and fingers active. I just want to forget the problems.....the stuff they pay the "big bucks" Ha. for.

Nuf Said.

Mark

 

[PondTunes]

Re: homemade power trim relay

Also if you did use two switches you could short it out if both switches were pushed in oppisite directions at the same time. Could happen pretty easily.

If you have a child in the boat maybe, or somebody mentally ill. I would hope that I would be the only person to tend to the switches in my boat. No offense intended. But I'm am happy with the way mine is setup, in my opinion. DPDT switch is a tilt/trim switch even recommended by the local marina.

Nobody said that the DPDT switch is wrong or that it shouldn't be done just from a simplicity & cost standpoint a pair of relays is the most logical route.

Ever seen those stupid warnings on products like "Do not use in shower" on a Hair dryer? Or how about "Do not use orally" on a toilet brush.. The sad fact is that these products wouldn't have those warnings if someone had not attempted it at one time or another.

Murphy's Law dictates that if it can happen it will happen.

With charging circuits being blown by reverse hookups and shorts it wouldn't be much fun replacing a rectifier after fixing the other damage caused by shorting out the two switches. A quick search should land you several threads that contain the text. "So I hooked the battery up the other way"

Throwing 12v to ground is never a good idea, why create the avenue for it to happen? If your setup has dual trim controls it probably is done so that there isn't a possibility of shorting them out.

 

[wildmaninal]

Need a power trim motor

Need a power trim motor

I hear ya PondTunes. Like I said no offense intended . Were would be a good place to search for possibly a used Calaco (if spelled right) power trim motor for a older model tilt trim unit? My brother's power trim went out and it is going to cost a pretty penny to have the motor rebuilt.

 

[dsujen]

Re: homemade power trim relay

Thanks to all and to guy74 especially. I bought the motor reversing relay and hooked it to 2 alarm door push buttons that i can work with my knees while I steer and use the throttle. The part that was the hardest to do was to remove the original shock and bolts from the manual trim. I had to use heat, penetrating oil and big hammers and punches to remove the old stuff. I also has to do some grinding to get the power unit to fit. It took all night to get the pins and bolts out. I bent every punch I had and smashed my hand and wrist in 3 places but I got er done and it works great.