Supplier of waterproof push buttons for engine panel

[gandy]

Hi,

Can anyone suggest a supplier for reasonable quality waterproof push button switches? This is for an engine panel. For the arrangement I'd like to have they need to be two pole changeover, to create an arrangement where pressing either Heat or Start will energise the engine instruments and alternator, and these stay energised until Stop is pressed. Any suggestions welcome, especially from anyone who's done this themselves. At the moment I have single pole N/O switches which would mean extra relays to create that function.

Thanks, Tony S

 

[Talulah]

Farnell http://uk.farnell.com
RS Components http://uk.rs-online.com

I have replaced the key switch before with push button switches. I used the waterproof vandal proof stainless switches.
Power: On/Off Latching switch
Start: Momentary action
Stop: Momentary action.
Our engine doesn't have pre-heat but another momentary action for pre-heat.

I also preferred switches that had a screw terminal instead of a spade or soldered terminal.

 

[Spirit of Glenans]

My boat has a Volvo -Penta engine and is fitted with a keyless switch panel made by VP. It has a "Heat", "Start" and "Stop" - buttons plus an engine-hour counter. One like it might suit you. Go to your Volvo-Penta dealer. Bring a chair for when they tell you the price!

 

[earlybird]

Hi,

For the arrangement I'd like to have they need to be two pole changeover, where pressing either Heat or Start will energise the engine instruments and alternator, and these stay energised until Stop is pressed.

Out of interest, how do you propose to achieve that with change-over switches?
Despite your reluctance to use them, I'd have thought relays would be by far the simplest way of achieving your design aim, and at low cost.
Or else a separate on/off power switch, like the conventional key-switch.

 

[gandy]

Out of interest, how do you propose to achieve that with change-over switches?

Hi, the circuit doesn't actually use the changeover function, but uses a mix of N/O and N/C poles. One relay is needed, energised by the second pole on either the Heat or Start button or by its own output, so it stays on once it's energised. The supply to the coil will be switched by the second pole on the Stop button which therefore needs to be N/C. If all the buttons are single pole N/O I'd need more relays and/or diodes as well. I might go for that if it's difficult to find the two pole push buttons. The panel is tight for space and I'd like to make room for the "Tiny Tach" which is currently fitted below, so I don't really want an additional on/off switch.

 

[earlybird]

Thanks; FWIIW, my panel uses 2 car-type relays and 3 n/o push buttons. The heater button powers the alarms but doesn't latch their supply.
Only the start button latches the supplies to alarms, alternator etc.

 

[gandy]

Thanks; FWIIW, my panel uses 2 car-type relays and 3 n/o push buttons. The heater button powers the alarms but doesn't latch their supply.
Only the start button latches the supplies to alarms, alternator etc.

Cheers, that would work. I'm not sure of the benefit from that heater button in your case, is that to test the lamps? I don't mind using more relays if I have to, but would like to avoid diodes after a nasty experience with a failed diode elsewhere.

 

[earlybird]

The heater button does test the lamps, except for the temp. alarm. A separate test button might be better though.
There is a diode from the start button to the relay coil, which is to prevent back-feed to the starter solenoid when the relay is latched on. Might be difficult to avoid.

 

[gandy]

There is a diode from the start button to the relay coil, which is to prevent back-feed to the starter solenoid when the relay is latched on. Might be difficult to avoid.

I can avoid the diode by using another relay, making three in total. Not sure to be honest now, is three relays better than two relays plus a diode? If I can't find those two pole push buttons that are ideally needed, maybe an on/off switch is the sensible option, or an On/Off/(On) toggle combining with the heaters, to save panel space.