U.S.A. HEADQUARTERS
P.O. Box 1306, Newport Beach, CA 92663
Phone: 714-751-0488 Fax: 714-957-1621
M38011500A
AsofJAN2004
150-A
ALTERNATOR NOISE FILTER
Installation/Operation Instructions
GENERAL INFORMATION
Alternators are a primary source of interference which affects the operation of lorans,
radios, depth sounders and other on-board electronics. The diode rectifiers in alterna-
tors produce a series of short high energy pulses which interfere with the electronic
equipment. In a loran, interference of this type causes cycle slip and/or loss of sync. In
radio receivers, there will often be a high pitched whine which varies with engine speed.
Troublesome “hash” can appear on depth sounder displays. The electrical interference,
or “noise”, is usually conducted from the alternator into the electronics via the
powerline wires, though it can also be radiated from the alternator lead much like a
transmitting antenna.
INSTALLATION
Caution: Disconnect the negative battery lead prior to filter installation. Do not run the engine with
the alternator output disconnected.
1) For best results, mount the filter on an engine mount, a wood deck beam or other
structural member as close to the alternator as possible. In some cases it may be neces-
sary to make up a special metal bracket in order to mount the filter near the alternator.
2) The filter case must be well-grounded, so if the case is not mounted directly to an
integral part of the ship or vehicle ground, connection must be made. Use a flexible
copper ground strap (available from NEWMAR) or a piece of battery cable, 6 gauge or
larger with appropriate terminals, which is no longer than 18". Attach the strap or cable
to the grounding stud (1/4-20) with the provided hardware. (See diagram on rear.) Se-
cure the filter using all four mounting holes and the provided hardware. Secure tightly
to ensure that vibration will not shake it loose when the engine is running.
3) Disconnect the positive lead from the battery. Wire the filter in series with the output
lead from the alternator lead as shown in the diagram on rear. If it is more convenient,
or if it will make a shorter run from the alternator to the filter, you may instead discon-
nect the alternator lead and connect the free end to the “BAT” terminal of the filter.
Then prepare a jumper cable of the same gauge with appropriate lugs and run it from the
alternator output terminal to the “ALT” terminal of the filter. If there is sufficient slack
in the original positive lead you may simply cut that cable at the appropriate point, in-
stall suitable lugs on the two cut ends, then attach them to the filter. (Note: Number 2
gauge wire or larger is required to carry 150 amps.)
4) Use the provided protective boots as well as electrical tape to cover all exposed con-
ductors to guard against accidental shorts. Check to make sure all wires are properly
connected. If the alternator is “floating” and has long ungrounded positive and negative
leads, use a separate 150A filter for each lead.
