Odd wiring situation with an autopilot...

[Rivers & creeks]

I was starting to wire in the autopilot today Raymarine type 300 running a type 3 style hydraulic pump. It has a 5amp glass fuse but it says the supply must be fitted with a 40amp circuit breaker???

1. What is the 5amp fuse for if the unit draws up to 40amp?
2. If it draws up to 40amp then it will kill the battery bank in a few hours so how much does it actually draw?
3. If it only draws 5 amps why does it need a 40amp breaker???
4. I was going to take the power from a fused lead, what fuse should that have or should I take it straight from the bus bar?

Thanks!

 

[sailorman]

I was starting to wire in the autopilot today Raymarine type 300 running a type 3 style hydraulic pump. It has a 5amp glass fuse but it says the supply must be fitted with a 40amp circuit breaker???

1. What is the 5amp fuse for if the unit draws up to 40amp?
2. If it draws up to 40amp then it will kill the battery bank in a few hours so how much does it actually draw?
3. If it only draws 5 amps why does it need a 40amp breaker???
4. I was going t take the power from a fused lead, what fuse should that have or should I take it straight from the bus bar?

Thanks!

is 5 amp protecting circuitry

 

[wooslehunter]

I've alwasy found the Raymarine guys very helpful. Juts give them a call & ask to speak with a technician.

 

[Playtime]

The 5A fuse will be for the electronics only. There should be a separate 40A circuit for the hydraulic drive.

 

[Rivers & creeks]

So assuming the circuit breaker is overload protection, it's probably drawing about 30amps peak? That requires some juicy cable? And if the sea is bad and it's running the pump a lot, that means a lot of power is being used!

 

[Playtime]

So assuming the circuit breaker is overload protection, it's probably drawing about 30amps peak? That requires some juicy cable? And if the sea is bad and it's running the pump a lot, that means a lot of power is being used!

Yes, but it will not be drawing 30A continuously! In worst case conditions it might consume 10 Ah per hour.

Did you not consider this before you bought the unit?

Presumably you have the Raymarine installation instructions?

 

[Rivers & creeks]

Did you not consider this before you bought the unit?

Not quite sure what I did to justify that comment?

And yes, I do have the instructions, that's how I know it says to use a 40amp circuit breaker. The instructions don't say why but the forum seems pretty certain that the anomaly of the 5amp fuse is that it's there to protect the circuitry.

 

[Martin_J]

Does this manual help...?
Type 100 and 300 course computer installations

Page 24 shows the 40Amp circuit breaker...

Page 42 shows the 25Amp fuse used to protect the Type 3 bypass valve...

Seems like there is also a 5Ampr relay on P37.. Perhaps this is protected in your cable loom.