(DG) ACU-300 Solenoid with other vendor's pump - 12V or 24V selectable?

[JBuss]

Hi,

My vessel is equipped with an old Radio Zeeland Euro 500 autopilot, which works with a constant running pump like E12172.

I'd like to have a Raymarine Autopilot and I wonder if the ACU-300 would be able to drive the existing solenoid valves.

The old constant running pump is running on 12V, while I'd like the ACU-300 run on 24V (which is my standard voltage on the vessel).

1. Can a 24V ACU-300 drive solenoid valves from a 12V constant running pump?

2. Is the ACU-300 suitable for working with a constant running pump from other vendors?

Thanks!

[Derek - Raymarine - Moderator]

Hi JBuss
Thankyou for your enquiry.

The ACU300 can be used to control the solenoids fitted to constant running pumps manufactured by other suppliers.

However, it is important that the solenoids conform to the following specification

Note: If power packs other than the Autohelm models are used the following
solenoid specifications must comply-

The pull in Voltage - less than 8V (16v for 24v systems)
The drop out Voltage - greater than 2V
The operating Current - less than 5A
The Solenoid Voltage must be the same as the course computer.
The response time of the solenoid valve is less than 150 to 180 milliseconds

Please note the oil viscosity, flow and pressure all effect the response time of the solenoids.

Please also note that 'flyback' diodes need to be fitted in parallel with the solenoid coils

regards

[Chuck - Raymarine - Moderator]

Content erroneously to FAQ:
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JBuss
RE: ACU300 and solenoids
Hi,

is that correct? I'm not a native speaker and I translate "pull in" with "value opens" and "drop out" with "valve closes".

So for the valve to open it needs LESS than 8V?
And for closing it needs MORE than 2V?

That would mean between 2V and 8V the valve would both open and close...?

And what is the flyover diode for? The ACU-300 documentation looks like I could simply wire the + and - of the solenoid directly to the appropriate ports on the ACU-300.

Thanks for any clarification!

--------------------------

Derek - Raymarine - Moderator
RE: ACU300 and solenoids
Hi JBuss

Many apologies, I should have written

The pull in Voltage - More than 8V (16v for 24v systems)
The drop out Voltage - Less than 2V

This means that the solenoid should effectively turn off or de-power once the voltage is below 2v - thus closing the valve. Also the solenoid will not activate until the voltage reaches 8V, (16v for 24v systems), thus opening the valve.

This allows to voltage hysteresis in the solenoids when opening and closing.
Many apologies
The flyback Diode, as explained, prevents damage to the ACU300 caused by the back emf voltage from the solenoid as the coil is energised and then de-energised.

There is a very detailed explanation click here if you want to read up more on this.

thanks