Voltage Sensor

[pdog]

Anybody know anything about this? Making a clicking noise and setting off my AC power alarm on the helm. Pic rotated left for some reason. I am talking about the white sensor to right of the red in pic.

 

[Captain Ralph]

Maybe; an old ACv polarity alarm.
These devices would sound if the black and white wires were bass ackwards.
Would also alarm if current was on the green lead.
Neither condition good.

Is this a new symptom?
Any changes in electric service?
Any electrical work done on the boat?

 

[pdog]

Yes its new. No electrical work done on boat on AC side or DC side for that matter.
The writing on this says its a single phase voltage sensor. Every time it clicks it sets off my AC power alarm on bridge. Lights etc do not blink when it clicks so I don't think the electric service into the boat is being disrupted although the alarm is indicating I am losing power.

 

[pdog]

No change in electrical service either.

 

[pdog]

It does not do it while running panel from generator instead of shore power.

 

[Captain Ralph]

Cycle shore and ship main breakers. IR shoot and check all shore power connects and those funny Hatteras fusses, would be my first steps.
Do you have transformers?

Orange Beach, uh?
Been awhile.

 

[pdog]

Not sure about transformers? Had electrician come by today to verify my 50 amp power service at my dock was functioning properly. All good there. Don't know what else to do except see if I can find a new sensor and swap it out.

Yep Orange Beach. Love it here but want to get a little farther south once kids are out of college.

 

[Captain Ralph]

IMO, there is current on the green lead.
Did the electrician detect any voltage on the green lead?
Was the alarm sounding while he was there?

 

[RichardM]

I went through the my electrical diagrams and there's not a lot that can set off that alarm. My boat is the same era and similar size so I'm guessing your electrical setup is very similar to mine. I also have the same white relay in my main electrical panel. The relay is 120 volts and is connected between the neutral and L1. It does not monitor L2. Basically, when 120 volts is present on L1, it will be energized and open the alarm circuit. It's a normally closed relay contact. It's not connected in any way to the ground and I can't really see how it would set off the alarm if a ground leak was present.

My feeling is that your relay coil is getting weak. It's energized as soon as there is AC power on the boat so it had a long working life. And since you say that the problem is not present when you're running on your generator also makes sense if the relay coil is tired. When you're running on your generator, you get a good 120/240 volts no matter the load. When you're on shore power, you actually never really get that much voltage. Sometimes a lot lower depending on the load on the marina shore power circuit you're on. If you get a lower voltage, and your relay coil is getting tired, you might get the occasional alarm without any visible effect on your AC lights (flickering). Just a thought. I might be wrong but that's my take on your issue.

Also, as others have mentioned before in this tread, you might want to check your L1 fuse near your shore power connection on the boat. Might be intermittent and you wouldn't see your light flicker if they're on L2. These fuses can get pretty hot if you're pulling the full 50 Amps and they have a limited life. I've seen those fail intermittently before. I replace mine once in a while with brand new ones and clean their holder. Personally, I always thought they were more of a fire hazard than a protection... One thing though, if it's not the relay acting on you, the problem seems to be between the shore power pedestal plug and the output of your transformer on your boat. I would check all accessible connections before doing anything else. It's a good thing to do when the boat gets old. Lots of fires start there.

Hope this helps ;-)

 

[MadHatter53]

I have one for my 32Vdc system and the 110/220V ac.

 

[madhatter1]

I have the same boat (1982 46) with that same exact relay. Last summer I noticed an occasional click from behind panel and traced it to this relay. Lights never flickered. AC units did not hiccup. No change in volts on meter or amps on either line. Tried to get drawings of this electrical switch panel but was not able to. Anyway just forgot about it and has not done it for quite a while.

Where is the alarm/indicator on the bridge? I would really like to know anytime the generator quits while underway.

 

[pdog]

Thanks for the reply guys. I have not checked that fuse yet but I will do that today. The light and alarm is on the same monitoring panel as all the engine alarms on the bridge.