Gai-tronics 732-102, 733-002 User Manual

Pub. 42004-147G

GAI-TRONICS® CORPORATION

A HUBBELL COMPANY

Model 702-002, 732-102, and 733-002

24 V DC Single-Party Amplifier Enclosures

Confidentiality Notice

This manual is provided solely as an operational, installation, and maintenance guide and contains
sensitive business and technical information that is confidential and proprietary to GAI-Tronics.
GAI-Tronics retains all intellectual property and other rights in or to the information contained herein,
and such information may only be used in connection with the operation of your GAI-Tronics product or
system. This manual may not be disclosed in any form, in whole or in part, directly or indirectly, to any
third party.

General Information

The following GAI-Tronics amplifier enclosures are covered in this manual:

Model Description

702-002 Indoor Amplifier Enclosure; single-party, 24 V dc input
732-102 Weatherproof Aluminum Amplifier Enclosure, single-party, 24 V dc input
733-002 Weatherproof Non-metallic Amplifier Enclosure, single-party, 24 V dc input

The amplifier enclosure is an important component of the 700 Series Page/Party® system. The Model
702-002 Indoor Amplifier Enclosure is constructed of fabricated steel. The Model 732-102 Outdoor
Enclosure is made of cast aluminum alloy, and the Model 733-002 Outdoor Enclosure is made of Valox
Both outdoor enclosures are extremely weatherproof and corrosion-resistant.

These enclosures are equipped with terminal strips for connecting inter-station cable. The 701 and 751
Series amplifiers mate directly with these enclosures.

Installation

CAUTION

indicated on the approval listing in the “Specifications” section of this manual. Such installation
may cause a safety hazard and consequent injury or property damage.

When installing an add-on station, consult the 24 V dc system layout diagrams at the end of this manual.
These figures, when used in conjunction with the station installation information and cable layout guide,
should provide all the information necessary to install additional Page/Party< stations.

Do not install this equipment in hazardous areas or areas other than those

®

.

GAI-Tronics Corporation 400 E. Wyomissing Ave. Mohnton, PA 19540 USA

610-777-1374  800-492-1212  Fax: [phone]

ISIT WWW.GAI-TRONICS.COM FOR PRODUCT LITERATURE AND MANUALS

V

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In 24-volt systems, plan on several branch lines from the dc source with no more than six stations per
branch. One branch could span up to 4,000 feet for a single station. The Maximum Cable Distance
Table lists the limits. Where two or more stations are listed, the assumption is that they are evenly
spaced along the cable.

Each amplifier contains two fuses on the PCBA in the 24 V dc input to protect and isolate the handset
and speaker amplifier circuitry in the event of a failure. Power line wiring to each amplifier or group of
amplifiers should have a fuse or circuit breaker to protect against wiring failures.

If cable with No. 14 AWG power line conductors is used, a 15-amp fuse or circuit breaker should be
installed for each branch line at the point it connects to the battery. Fuse or circuit breaker rating is
determined by the size cable used in the branch. Consult the National Electrical Code (NFPA70) or
Canadian Standards Association (CSA 22.1) for the maximum allowable capacity of the wire used.

The GAI-Tronics 24 V dc series of Page/Party

®

system equipment is designed to operate from a 24-volt

dc rechargeable battery. A battery charger may be connected to the battery to maintain the charge.

CAUTION

Under NO condition should this equipment be operated from a battery

charger without the batteries connected.

Most chargers have an unloaded output of 35 to 45 volts that can quickly damage the equipment designed
for nominal 24 volts. To maintain a proper state of battery charge, the voltage across the batteries will be
somewhat greater than 24 volts, but should never exceed 28.8 V dc. Grounding the negative side of the
battery system at only one point is recommended and will ensure hum- and noise-free operation.

Enclosure Placement

All GAI-Tronics Page/Party® units are wired in parallel. Good system layout design minimizes the cable
required for each installation. GAI-Tronics multi-conductor cable, designed especially for this
application, is recommended. The number, size, and color-coding of conductors are listed in the
accompanying system connection diagrams.

System layout and power cable length are important considerations when installing Page/Party
equipment. Consult the Maximum Cable Distance table for typical cable lengths. The cable distance
between stations as well as total cable distance must be considered. Cable distance is more strictly
regulated in 24 V dc systems because of the amount of resistance these cables encounter—the longer the
cable distance, the greater the resistance and IR losses (voltage drop) encountered.

®

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Model 702-002, 732-102, and 733-002 24 V DC Single-Party Amplifier Enclosures Page: 3 of 12

Maximum Cable Distance in Feet*

Number
of Units

No. 14 AWG

Total/Between

No. 12 AWG

Total/Between

No. 10 AWG

Total/Between

No. 8 AWG

Total/Between

1 4,000/4,000 6,400/6,400 10,000/10,000 16,000/16,000
2 2,800/1,400 4,480/2,240 7,000/3,500 11,200/5,600
3 2,000/660 3,200/1,060 5,000/1,667 8,000/2,667
6 1,200/200 1,920/320 3,000/500 4,800/800
9 800/90 1,280/142 2,000/222 3,200/356

*Based on the following assumptions:

• GAI-Tronics-supplied cable is used.

• Speech signals (Speech signals do not have the energy content of a continuous tone, and therefore do

not require as much average current.) N

OTE: With continuous tone signals, each station is driven to

12 watts and the distances stated should be reduced by half, or ideally one fourth, to minimize signal
distortion.

• Wire resistance (ohms) is the nominal value for the applicable AWG at 1,000 feet of bare copper,

stranded wire @ 20º C (68º F). Wire resistance values used are as follows:
14 AWG = ~2.525 ohms; 12 AWG = ~1.588 ohms; 10 AWG = ~0.999 ohm; 8 AWG = ~0.628 ohm

• DC V at cable run’s feed point = ~26.6 V dc

• DC V at the last unit in cable run = 21 V dc minimum

• Unit current draw (I) is the same regardless of the unit’s placement along the cable run for ease of

calculation. (~1.1 amperes when unit is producing a 12-watt sine wave output.)

For conditions other than above, the following formula may be helpful in calculating the approximate
maximum distance for a single station.

For continuous tone applications

For speech operation only

with minimum distortion:

, multiply the above result by a factor of 2 to a maximum factor of 4.

Example: What is the approximate maximum distance for a single dc station if the voltage feed is 27.5
V dc and a No. 14 AWG wire is used @ 20º C?

Info:

• No. 14 AWG @ 20º C = ~0.002525 ohms per foot

• Vfeedpoint = 27.5 V dc

Solution:
(27.5 V – 21 V) / ((2 × 0.002525 ohm per foot) × 1.1 amp)

= 6.5 / 0.005555
= 1170 feet (for continuous tone signal) or up to ~4680 feet (× 4) for speech signals

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Mounting

The Model 732-102 Weatherproof Metallic Enclosure is supplied with pre-drilled cable openings and
conduit hubs with top and bottom cap plugs in place to prevent contamination. The Model 702-002
Indoor Enclosure and the Model 733-002 Weatherproof Non-metallic Enclosure are not supplied with
conduit or cable openings.

Drill or punch these openings using the template supplied before mounting the enclosure. The
recommended cable entry point is via the bottom of the enclosure near the rear surface to prevent
moisture from dripping onto the terminals or PCBAs. A secondary location for cable entry is in the top
of the enclosure toward the sides. Avoid the top center, as it may interfere with the plug-in amplifier
receptacle. Under no circumstances should cable entries be made in the side of the enclosure as this may
interfere with the installation of the plug-in amplifier.

For specific details including mounting hole dimensions, refer to Figure 1 for the Model 702-002 Indoor
Enclosure, Figure 2 for Model 733-002 Weatherproof Non-metallic Enclosure, and Figure 3 for the
Model 732-102 Weatherproof Metallic Enclosure. When mounting the enclosure, use caution to avoid
damaging the terminal blocks inside. The suggested mounting height for all station enclosures is
54 inches (137 cm) up to the centerline of the enclosure.

Figure 1. Model 702-002 Indoor Enclosure Mounting Details

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