Battery Maintainer (Bi-Directional Isolator Relay Delay); Relays - Monaco 2009 Knight Owner's Manual

BATTERY MAINTAINER (BI-DIREcTIONAL
ISOLATOR RELAY DELAY)
The Battery
Maintainer
(Bi-Directional
Isolator Relay
Delay) constantly
senses voltage
Located in front roadside
electrical panel
of the house and
chassis batteries.
With engine running, both the house and
chassis batteries are charged from the engine
alternator. When the motorhome is plugged
into shore power or operating from the
generator, both the house and chassis batteries
are charged from the inverter. If neither
battery is being charged, the batteries are fully
isolated.
The battery maintainer also senses heavy
loads on either battery to prevent the wrong
battery from inadvertently discharging.

Relays

The motorhome uses various
relays to operate electrical
equipment, such as lights and
motors. If a relay needs replaced,
carefully record the location of
each wire and all markings or
labels.
Relays can look the same in appearance,
but differ in function. Note on the side of the
relay a schematic drawing identifying the
relay as 87 or 87a. These current ratings differ,
and if mixed, will create problems. Ensure the
replacement relay is of the current rating to
assure proper operation.
Another indicator to the type of relay is the
post or legs. Turn the relay over and look at the
post.
Note the differences between the numbered
posts:
1. The 30 post is the incoming fuse
and/or breaker power. Some relay
applications supply power to the 30
090518b
post. Some use it for ground. The
30 post can be used many different
ways.
2. The 85 post is one side of the coil,
tripped different ways.
3. The 86 post is the opposite side of the
coil, tripped different ways.
4. The 87 posts are not common to the
30 post until the relay is tripped.
When the relay trips, both 87 posts
are common to the 30 post.
5. Using an 87a relay, the 30 post and
the 87a
post are
common.
When the
coil is
tripped, the
87a post
becomes
inactive
and the
30 post
080406
becomes
common to
the 87 post
located on
the outside
of the relay.
Single Pole Single Throw Relay.
A Single Pole Single Throw relay (SPST) is
an electro-magnetic switch consisting of a coil
(terminals 85 & 86), one common terminal
(30), one normally closed terminal (87a), and
one normally open terminal (87).
When the coil of the relay is at rest (not
energized) the common terminal (30) and
the normally closed terminal (87a) have
continuity. When the coil is energized, the
common terminal (30) and the normally open
terminal (87) have continuity.
NOTE
When there is power applied to the
coil, the coil sets up a magnetic field
in the windings. When the power
is removed, the field collapses. A
momentary high voltage discharge
will occur. This is how an ignition coil
works.
080405b
080405c
080405d
080405
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