What kind of dimmer is this?

I've got a Grand Banks Eastbay and a few lights need replacing. Several circuits have a rotary dimmer on them. Anyone know what kind of dimmer they use?

Attached is a picture of the backside of the dimmer in the switch box. I don't know if it's just cutting resistance via the rheostat or if it's connecting to some other dimming module 'somewhere else'. The thin gauge of the wire at the rotary knob makes me think there's a module somewhere else.

Anyone seen this sort of thing?

My next question is what kinds of LED bulbs are known to be compatible with this sort of dimmer?

Most dimmers create a square wave signal, varying the "on" wave length depending on where the knob is. Rarely a rheostat as that makes a bunch of heat.

I know in my house, some LED bulbs are dimmable, presumably using the same sq wave dimmers, but on a boat, no idea. You will need to talk to the LED vendors.

Or just try it.

wkearney99 said:

I've got a Grand Banks Eastbay and a few lights need replacing. Several circuits have a rotary dimmer on them. Anyone know what kind of dimmer they use?

Attached is a picture of the backside of the dimmer in the switch box. I don't know if it's just cutting resistance via the rheostat or if it's connecting to some other dimming module 'somewhere else'. The thin gauge of the wire at the rotary knob makes me think there's a module somewhere else.

Anyone seen this sort of thing?

Click to expand...

By the look of the photo it's a Pot of sorts, likely wired to a dimming module either at the back of the breaker panel or ....unlikely that the module is buried at the feed point of a lighting circuit. I think even if the dimmer was not entirely compatible, you will still get partial dimming ( enough for the purpose ) ............... my .02 fb

Ex Sailor said:

By the look of the photo it's a Pot of sorts, likely wired to a dimming module either at the back of the breaker panel or ....unlikely that the module is buried at the feed point of a lighting circuit. I think even if the dimmer was not entirely compatible, you will still get partial dimming ( enough for the purpose ) ............... my .02 fb

Click to expand...

I've yet to come across any modules, but then I haven't gone digging too much yet. I've got one or two circuits that exhibit some flickering, and this is with just incandescent bulbs in them. Near as I can tell, nothing's been replaced with LED yet, at least not on the circuits that have some intermittent pulsing. I'm guessing whatever dimmer module these use is likewise in need of replacement. If I could stick with the existing knobs to control their replacements that would be great. They're Vimar wall plates and switches.

I'm familiar enough with LEDs to know about their current requirements and potential dimmer complications. I'm definitely interested in buying the correct kind of LEDs, not just something that'll work ok 'for a while'.

I've e-mailed the Marine Beam folks for info, as well.

We changed a bunch of G4 halogens to leds in our van. We found we had to leave one halogen in the string for the dimmer to work properly (don’t ask me what kind of dimmer it is). It seems the leds by themselves weren’t enough of a load for the dimmer and this was an easy fix.

I dunno what kind of dimmers we have, but I suspect PWM. The actuator is a rotary knob (Vimar product), but I dunno what's behind all that. OTOH, at least I can say we've got a boatload of these and they work on our three dimming circuits:

https://store.marinebeam.com/12-led-side-pin-g4-replacement-bulb-sp-g4-12/

From other owners, I had thought maybe we'd have to keep one halogen bulb in the circuit but... because they did... but we don't. I don't know if that's a function of the type of dimmer we have, or the type of G4 LEDs we bought, or the number of G4s on the circuit, or all of that, or something else entirely.

-Chris

Correct, some dimmers (at least in residential AC setups) have minimum wattage needs else they'll cause problems. This is most often caused by dimmers that use the light as part of their circuit (typically switches that operate with no AC neutral). There's a trickle that would normally go through an incandescent bulb without illuminating it. LEDs, however, often see just enough voltage to power their circuit. This is often seen as flickering or lights that won't stay turned off. Not sure how DC dimmers handle this, as I've not worked with any but I'd venture there's potential for similar complications.

Thus knowing what dimmers I have in there now will help determine which LED replacements will work properly. Or at least prepare me for the added effort of replacing the dimmers with something better suited to the proper LEDs.

http://www.trawlerforum.com/forums/s4/anyone-know-where-x2-37029.html

I went ahead and put LEDs on this dimmer in he PH. It does emit a whin at full power so I have to back it off a bit.

Still looking for a few LED PWM dimmers.

Took some digging but I finally found one of the dimmers. It was buried inside the pillar.

I didn't have the time to throw a voltmeter on there to check the voltage, nor the dimmer rheostat resistance.

At least now I know what's in there. I know the one in the forward stateroom has a problem, it flickers with even just incandescent bulbs in it. That'll be first on the list for replacement. Might as well make the jump to LEDs and a new dimmer at the same time. I'm going to reach out of DRSA to learn more.

Made some progress on this. Put an Anigmo dimmer in as a replacement, and it's working quite nicely. Re-wiring the circuit though, was a huge pain in the ass. The old dimmer shared the negative. The new dimmer requires the lights be on their own loop from the dimmer. Should be an easy swap, right? Oh no... not even close.

Power to the circuit came into the switch by the forward starboard door. But the dimmer is buried in a pillar alongside the aft door. It's a 3-way light setup. Ok, not too much trouble, as the dimmer doesn't require constant power, so switching it's positive through the 3-way setup is fine. But there was NO negative wiring in the pillar going up to the 6 ceiling lights. This took some chasing down. Turns out the negative was coming off the forward port ceiling light. I had to clip that and run a single wire from the dimmer's negative PWM terminal to the nearest ceiling light. Which took a bit of panel removing, fish tape, a liberal sprinkling of profanities.... AND time.

I have three other dimmer circuits and it looks like they're going to be similarly adventurous to install.

An annoying part is the Anigmo dimmer wants a 100k potentiometer to control it. Two of the units I ordered would not crank to a full 100k of resistance (only 94 and 96k respectively). The dimmer did not like this and would cause the LEDs to flicker. I could just add a resistor to tweak the value, and may do that. But I didn't have any spare resistors on hand, and thankfully ONE of the pots could crank past 100k (to 106k according to my multimeter). Keep this in mind if you're entertaining the idea of replacing dimmers... check the resistance values before schlepping all the way to the boat!