Ac c, Utomatic, Rossover – Sterling Power Products AC32A User Manual

Page 3: Witch, Nstructions

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A

UTOMATIC

AC C

ROSSOVER

S

WITCH

I

NSTRUCTIONS

Thank you for purchasing the Sterling Automatic AC Crossover Switch, a sophisticated product which will help
you to safely and comfortably switch your

power sources on board.

M

AIN

P

RODUCT

F

EATURES

The Sterling Automatic AC Crossover Switch is a three-stage sequential switch which will automatically switch
the AC power sources on board. It will ensure that only one AC power source will be on your boat’s ring mains
at any one time, thereby protecting your electrical equipment from possible damage.

The complexity of the system is masked by its easy installation and fully automatic operation. Basically, the unit
is a three-stage sequential switch with the channel marked “shore power” as the priority selection. The channel
marked “generator” is second, and the channel marked “inverter” is third. This default setting works on the
assumption that the boat has shore power, a generator and an inverter. However, some boats may have 2
generators and no inverters, in which case you can simply use the inverter port as another generator port etc. In
fact, you can mix and match as you wish. There are a few things which are unique to each channel but these do
not affect the channels from being used for an input source other than the default.

It is important to stress that this system operates by itself in fully automatic mode and requires no human
intervention. However, for more complicated systems, the Sterling Automatic AC Crossover Switch offers many
additional and sophisticated features.

I

NSTALLATION (see Fig. 1)

Cable Connections

System Components

This channel has a 10-

second delay in order to allow the generator to fire up and to reduce the high voltage surge associated with
generator startups. (All other channels work on about a 1 second delay.)

AC

Remove the screws from each end of the unit to remove the end caps. The p.c.b. can slide about 1 - 2 inches
either way to expose the screw connectors for installing the cable. Slide the cables through the slots in the end
caps (If required, you can make the openings slightly bigger.). For 32A three-core cable, the outer cable sheath
will need to be removed to enable the smaller internal insulated cables to be worked on with ease.

Connect cables as per drawing. Run the wires through the cable ties. When the wiring is completed, the cable ties
can be pulled tight to lock and fix the wiring. Replace the end caps.

Before starting to install the unit,

please read and understand these instructions completely, in order to avoid any possible safety risks and to
avoid any danger of damaging the unit or your boat / vehicle.

All high voltage input and output connections must be totally isolated before working on the circuits or
this unit! It is strongly advised that any work being performed on high voltage equipment or circuits must
be done by professionals only.

This unit comes set up as standard for use with either 110V or 230V, 40Hz - 60Hz with a current rating of
32A. Each input channel is fused at 32A. For safety, the internal relay control system is rated at 40A
continuous.

Install the unit as per wiring diagram. Ensure that the cables being used have the correct
rating and size for the power being applied. Fit in a cool, dry and well ventilated place.

This channel

is the only channel with reverse polarity warning.

Shore power input:

Generator input:

Connect live to L and neutral to N on the screw terminals. The fuse beside the connection

block is a 32 amp fuse. In the event of this fuse blowing, simply replace it and check why the rating of the
equipment was exceeded. Please ensure that adequate cable is used to cover the usage on the boat.

Connect live to L and neutral to N on the screw terminals. The power source does not

necessarily have to be a generator. It could also be an inverter or any other a/c power source; it is simply the next
channel which the system will engage, when and if the shore power is disconnected.

A

B

2

This is a low power signal only and is not to be used as a power connection!

AC

:

if

Inverter / Generator Input:

A/C Ring Main Output:

Earth Connections:

Battery Charger Disengage Signal:

Onboard Consumer Unit A/C Distribution Board:

A/C Generator Input

Shore Power Input Socket:

Inverter:

Zinc Saver / Galvanic Isolator:

Remote Display:

Connect live to L and neutral to N on the screw terminals. The power source

does not necessarily have to be an inverter. It could also be a generator or any other a/c power source. It is simply
the channel with the lowest priority. The inverter channel also controls a signal which can be used to isolate your
battery charger when the inverter is on line. This is to prevent the inverter operating your charger which can lead
to an ever decreasing power loop.

This is the main a/c output, and should be connected to an earth leakage detector of

some form (R.C.D) and then to a fused distribution box.

All the earth lines are connected to the same point, and this point should be grounded to

the boat’s bonding system to comply with European and American regulations.

This connection

provides a signal to switch a relay which is connected to your battery charger’s a/c input, thus preventing the
charger to work at the same time as the inverter.

This should contain your main R.C.D. (earth leakage

detector) and fuses for distributing the a/c power around the boat. Note that an R.C.D. is a requirement for any
boat with a/c power on board! The Sterling automatic crossover switch is not an R.C.D.

The maximum current rating of the unit is 32A which is about 7kW at 230V or 3.5kW

at 110V. Therefore,

Most European shore sockets are about 16A. The maximum current rating of the

automatic crossover switch 32A, so there should not be any problems with most shore power supplies.

The maximum current rating of the unit is 32A which is about 7kW at 230V or 3.5kW at 110V.

Therefore,

The same applies if a

second generator is used instead of an inverter.

Protects the boat from stray electric corrosion coming up the earth cable and

destroying the zinc and other metals on the boat. For more information on this, please refer to our web site
regarding this highly recommended product which is available from your local Sterling stockist.

The remote display gives the following basic information:

Green light on: This shows the channel which is currently being used.

Green light flashing: Power is available on this channel, but it is not the power currently being used.

Red light flashing: Fault on p.c.b. Either the relays have become defective, or a internal fuse has blown. It will
not show which fuse, and it is up to you to test them, but it will most likely be the shore power fuse.

Red light on: This indicates reverse polarity on the shore power input. It is then up to you what you do about
this. We strongly recommend you stop using the a/c shore power until such time as the marina or an electrician
has fixed the problem.

The Sterling AC Automatic Crossover Switch comes with the ability to

shut down the battery charger if it is on the boat’s ring mains. You may wish to use this feature because when the
inverter is on line, you certainly do not want to run the battery charger from the inverter.

In order to remove the need to remember to switch the battery charger off every time you start the inverter, you
can use a suitable standard 230V (or 110V depending on your setup) relay available from your local electrical
wholesaler. Connect the relay to your battery charger’s main feed. The relay energising circuit should then be fed

directly to the AC crossover switch control circuit

. The AC power control circuit is normally in the open

position and closes when the inverter circuit is on line. So when the control circuit closes, it will energise your

battery charger control relay

and thereby open the charger relay

.

Warning:

Do not under any

circumstances try to feed the main battery charger power directly into the control circuit on the

crossover switch! The control must be done through a relay (contactor)!

if you have a larger generator set, do not direct all the power through the switch!

you have a larger inverter, do not direct all the power through the switch!

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