HAIDA's ELECTRICAL SYSTEM

All photos by Jerry Proc

 
INTRODUCTION

HAIDA's electrical system consists of the elements listed below. It is important to note that a generator produces Direct Current (DC) power while an alternator produces Alternating Current (AC). The prefix "turbo" means that the prime mover is a stream-driven turbine. To be correct to HAIDA's years of service (1943-1963),  the term cps (cycles per second) is used versus the term Hertz (Hz) which started coming into usage in the mid 1960's.

TURBO-GENERATORS

Two, 200 kilowatt turbo-generators produced 225 volts of Direct Current.  This power was distributed from the generators to the main switchboard located in the Low Power Room (mid-ships) and the aft switchboard in the Gearing Room. These two switchboards are inter-connected so that power could still be supplied throughout the ship even if a portion of the system was damaged. All of the lighting and any motor driven equipment such as ventilation fans or pumps ran from 225 volt power. The switchboard also permitted the ship's electrical load to be transferred from ship's own power to shore power when berthed.
 

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Starboard turbo generator - front view 
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Turbo generator - end view #1 
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Turbo generator - end view #2.
 
DIESEL GENERATORS

When shore power was not available, internal power could be produced from either of two auxiliary 60 kw diesel generators. These were originally Paxman 6 cylinder units last built in 1952 but fitted on all  the Tribals built in the UK. Later on, the Paxman units were replaced with 100 kw diesel generators likely during the 1949/52 refit. Each 100 kw, 225 volt DC  generator is powered by a three cyliner General Motors (Model  3-268) diesel engine. The forward generator is fitted in Boiler room #1 while  the aft one was in the aft portion of the Gearing Room.  The aft generator has been restored to functional order by Stoker Marg Mathers and is still capable of providing power to the ship.
 

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Front view of the GM 3-268 diesel generator. The generator itself is at the back of the engine. 
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This is the "business" end of the diesel generator.
 
SWITCHBOARDS

The forward switch board is supplied by one 200 Kw generator fused at 900 amps and one 100 KW generator fused at 300 amps. There is a tie disconnect in the middle of the board rated at 1000 amps and two interconnecting disconnects are rated at 600 amps each. The after board is supplied by the other two generators with the same switching capabilities and capacities.

The aft switchboard identifies circuits starting from the letter A onwards  while the forward board appends the number 1 after each letter.  Example  A circuit on the forward board would be designated  'B1' but on the after board, it would be just  be a 'B. All major equipment such as weapons are fed from both boards through an automatic change over switch at each unit in case the power source fails The interesting thing is that  the designators are not in direct correspondence with each other. As an example a power feed to a weapon could be from the forward feed and designated 'C1' while the aft feed might be designated  'K'.
 

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Main switchboard - Looking at the aft bulkhead of the Low Power compartment towards starboard. Due to safety considerations, this compartment cannot be opened up to the visiting public since the switchboard in this compartment is "live". 
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Aft switchboard looking towards port. It was located in its own compartment within the Gearing Room. Due to safety considerations, the Gearing Room is not open to the public.
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Aft switchboard looking towards starboard.
 
LOW POWER SYSTEM

The Secondary or "low-power" system is a  24 (nominal) volt D.C. system which is used to operate equipment such as gyro repeaters, plot tables and in an emergency, some of the radio equipment. When running, the system measures at 22 volts.

There was also a battery bank - 250 amp hours and normally one LP M/G and battery bank were run in parallel with trickle charge being applied.  Also, there were two types of LP circuits - two wire for such things as M-type transmitters, FC motors etc and earth return for such things as gunnery firing circuits.
 

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A pair of 24 volt DC motor generators form the heart of  the Low Power system.
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Forward bulkhead of the Low Power compartment looking towards port.
AC SYSTEM

As more and more North American electronics was fitted in the ship, there became a need to produce alternating current in large quantity. To facilitate this, two 50 kilowatt motor-alternators (M-As) were installed. One is located aft, adjacent to Radio 2 in the aft KVA compartment.  The forward KVA compartment is located below the After-Lower Mess deck. These M-As produce 440 volt,  3 phase (delta), 60 cps AC power and each is rated at 50 kilo-volt-amps (KVA) . Examples of loads requiring 3 phase power include the 3in 50 gun mount and the sonar equipment.. The motor for the AN/SPS6-C radar antenna requires a 440 VAC, single phase feed. The 440 volt output is stepped down to 120 volts three phase using a 440/120 delta-delta  transformer in order to power the bulk of the electronic equipment aboard ship. There is no neutral conductor in the system.

The forward M-A set has it stepdown transformer beside the control panel in the Electrical Workshop while the aft unit has its transformer behind the control panel next to the set.

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This is the restored aft KVA compartment. Note the ventilation (3L) shroud surrounding the motor-alternator set. The deck was restored in 2009 and the remainder of the compartment restored in 2010.
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Full view of the 50 KVA motor-alternator. The motor is on the left and the alternator on the right. The device atop the alternator is known as an exciter. It a small DC generator to supply the power that creates a magnetic field in the alternator.  By varying  the current provided by the exciter, the output voltage could be controlled. Frequency is controlled by varying the speed of the drive motor.

 
DIESEL GENERATOR BATTERIES

Each of the General Motors 3-268 diesel-generators also need a 60 volt cranking battery. When the ship was in service, this battery consisted of ten, 6 volt batteries wired in series. Today, the battery for the aft (restored) diesel consists of  five,  series-wired, 12 volt, 950 (cranking) amp truck batteries.
 

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This is the 3-268 starting battery for the aft diesel generator.
 
*120 VAC 400 CPS  SOURCE

Also fitted were two 120 volt 400 Hertz motor alternators which supplied power to parts of the weapons system, plot table system and the gyro compass. These were located in the forward "KVA" compartment  area.

* 200 VAC 1100 CPS SOURCE was applied to the servo amplifiers fitted to the starboard side of the Transmitting Station.

* 50V 50CPS  for indicator magslips.

* 120V 333cps (motor-alternator) for the gyro roll units in the Squid and gunnery systems.

* 20v 1100cps for power magslips.
 

OTHER ASPECTS OF HAIDA's ELECTRICAL SYSTEM
 
For all practical purposes, all of HAIDA's lighting has been restored to run on 220 VDC by Shipkeeper Jim Brewer. This is a project which spanned several years. An industrial-strength rectifier, (not part of the ship's original kit) provides just slightly less than 220 volts. This slight undervoltage is desirable since it will extend the life of the light bulbs.

 
electrical_ panel_radio1.jpg
This is the distribution panel for Radio 1 and 3 and is situated in Radio 1. Radio 2 gets its feed from the aft 120 system while Radio 4 is fed from the transformer in the radar equipment space.
This small switchboard distributed emergency 12 VDC  power to various pieces of gear in Radio 1. It obtained its feed from a bank of batteries located in a sealed enclosure on the other side of the bulkhead
electrical_post.jpg
Located in strategic positions, these heavy duty binding posts would be used to bypass a damaged compartment by providing an electrical feed to undamaged sections of the distribution bus. The bypass cables, which are terminated with huge lugs,  were hung in the vicinity of the binding posts. Both the positive and negative 220 VDC lines have their own binding posts. 
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Small electrical repairs were carried out in the Electrical Workshop. It is still in constant use by HAIDA's shipkeeper. 

 

Additional Contributors or Credits:

1) Jim Brewer <snack.235(at)sympatico.ca>
 

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Mar 25/14