05301-032
USER'S/COMMISSIONING
HANDBOOK
FOR
JTM DIMMER RACKS
RANK STRAND ELECTRIC
29 King Street London WC2
Telephone 01-838 4444 Telegrams Spotlite London WC2
A DIVISION OF
RANK AUDIO VISUAL LIMITED
05301- 032/Title /Page 2
This handbook contains information normally required for
installation and commissioning of the equipment. Maintenance
information, where relevant, is covered in the associated
Maintenance Handbook.
SCOPE
SER VICE ASSISTANCE
For assistance with servicing or maintenance, please contact
the nearest branch office, agent or associate company (see
list attached at the end of this handbook) and state the Order
Reference, Equipment Reference or other relevant
information as well as an indication of the fault-symptom
encountered.
Revision/amendment since last issue of document:
~
or•
1 or~
on margin denotes minor changes.
against headings or illustration numbers denotes
major revisions.
Issue 2
7101
~
~
05301-032
Page 1 of 11
USER'S/ COMMISSIONING
HANDBOOK
1. General Information
1. 1. Equipment
2. Construction & Layout
2. 1. Racks
2. 2. Dimmer Modules
2. 3. Trigger Units
3. Installation & Connections
3. 1. Installation
3. 2. Ventilation
3. 3. Mounting
3. 4. Connections
JTM 10/20-way DIMMER RACKS
CONTENTS
Page
2
2
3
3
3
3
3
5
5
5
5
4. Setting-up Information
4. 1. Dimmer Modules
Photographic Illustrations:
SUPPLEMENTS
Publication 1-014: List of Regional Offices, Agents and
Associate Companies .
Figs. 2. 1. 1 & 2. 1. 2 :
Figs. 2. 2 & 2. 3:
9
9
10
11
7101 Issue 2
05301-032/Page 2 of 11
1. GENERAL INFORMATION
JTM Dimmer Racks are designed for use with the standard range of
Rank Strand Control Desks and other Control Panels, to provide a
lighting-control installation for stage or studio use. This handbook
deals primarily with the Dimmer Racks.
Each Rack houses a set of Dimmer Modules with the associated fuses/
circuit-breakers, fan and other electrical items.
1. 1. EQUIPMENT
1. 1. 1 . RACKS
The standard range of JTM Dimmer Racks is available in the
fol.lowing variations:
l
Number of channels per rack:
Supply voltage requirements :
Supply frequency:
Total KW rating of Dimmers:
Rack JTM- 20 ( 20-way racks):
Rack JTM-10 (10-way racks):
A suppressor Unit is supplied with each rack or groups of racks.
1. 1. 2 . DIMMER MODULES
The following table lists the range of Dimmer Modules. The
Ref Number is shown on a label fixed to the Module base-plate
lKW
KW 2KW JTM20
3KW
RATING SKW
6KW
10-way or 20-way.
110-120V or 200-250V;
I-phase or 3-phase 4-wire,
and earth.
Sn or 60 Hz.
l00KW max. (200-250V supply);
60KW max. (l 10-120V supply).
S0KW max. (200-250V supply);
30KW max. ( 11 0- l 20V supply).
VOLTAGE RATING
200-250V l 10- l 20V
,,,
,,,
JTMl0 JTMl0C
-
-
..i ........
....... , ..
JTM20C JTM20L JTM20 LC
-
JTMS0C
- -
,,_
,,,
-
JTM30L JTM30 LC
-
JTM60L
(see Note
1)
.. 1 .... , ..
.. , .... , ...
-
-
-
,,
,.
~ Issue 2
I
,,_
,,,
.. , .... , ..
"'&'",.I"
Note 1: The filter unit is mounted on a separate base-plate .
With laminated-core filter unit .
:
With C-core filter unit .
:
7101
2. CONSTRUCTION AND LAY -OUT
2. 1. RACKS
See Figures 2. 1. 1 and 2 . 1. 2 on page 10, and figures 2. 1. 3 and
2 . 1. 4 on page 4 .
The racks are of totally enclosed construction designed for
installation as free-standing units. An integral bracket with holes is
provided at the top pf each rack to enable securing to a wall or
vertical surface: alternatively two similar racks may be mounted
back-to-back and secured to each other. The fuse-panel on 200- 250V
racks or the circuit-breaker panel on 110- 120V racks is hinged to
provide access to the terminal compartment. The Dimmer Modules
are mounted in the remaining part of the rack in columns ( of 3 and 7
in JTM-10 racks, and 4, 8 and 8 in JTM.,.20 racks), and metal
panels secured by screws provide access for maintenance purposes.
The interior of the rack is force-ventilated by an expeller fan
mounted on top; air-entry is via a grill at bottom front of the rack.
05301-032/Page 3 of 11
Each rack or group of racks is supplied with a totally enclosed
Suppressor Unit to prevent transmission of switching transients into
the mains-supply wiring.
2. 2. DIMMER MODULES
Fig. 2. 2 (page 1 I) shows the lay-out and construction of a typical
2 - to - · 5 KW Module .
The Ref. No. for the module is shown on a label affixed to the baseplate. Letter-suffix C to the Ref. No. indicates that the filter unit is
of C-core design; letter-suffix L denotes that the module is designed
for 110-120V supply.
On Modules with plug-in Trigger cards, the plug-in connector is
mounted on top of the heat- sinks.
On 110-120V (L) modules, a fuse is mounted across studs Fland F2
(Fig. 2. 2) for protection over-riding the circuit-breaker for the
channel.
2. 3. TRIGGER UNITS
See Fig. 2. 3 (page 11) for the component lay-out which is identical for
the wired-in and the plug-in boards.
3. INSTALLATION AND CONNECTIONS
NOTE: Each ra.ck or group of racks is supplied with a Ref. 855
Suppressor Unit consisting of four capacitors. Mount this Unit close to
7101
Issue 2
05301-032/Page 4 of 11
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arm a
lTIIll
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I r. I
10-way
Rack
l~l
Overall Dimensions: A=660mm (26"); B=l570mm (61. 75"); C=280mm (11");
D=965mm (38" ).
Fixing Dimensions: E=267mm (10. 5"); F=24lmm (9. 5"); G=l78mm (7").
-...J C
I
B
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IT]] 0
DTIIl
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20-way
Rack
-
-~
o4. --1 0 0
lr-il
I
I I
Fig.2 .1.3-Racks.
Fig.2./.4-Suppressor Unit.
Is sue 1
Terminal
,, Cover
I , dD
133mm
T
,...-
160..-im
6%,1'
~
,,
133.,,,.,,,
~5¼''---
-$--~ -G>-
1 I fjz.,,.,,,
-Q)- -- -El)•-= t}f'
Mounting Holes
I
7003
05301- 032/Page 5 of 11
the incoming mains- supply bus bars; see Fig. 2. 1. 4 for dimensions and
para. 3. 4.below for connections.
3. 1. INSTALLATION
To minimise expensive cable-runs to the lamp loads, site the racks
as near to the loads as practicable. Where possible, group two or
more racks together at one location. Avoid any acoustically 'live'
position in the acting or audience area.
An adequately fused isolator for the incoming mains-supply must be
provided near to each rack or group of racks.
In choosing the location for individual or grouped racks, ensure that
free flow of air through each rack (air-inlet at bottom and outlet at
top) is not impeded in any way. Also allow enough clearance to the
left of the rack to allow the fuse or contact-breaker panels to be
hinged open more than 90° and permit free access to the terminals.
3. 2. VENTILATION
The force-vent fan in each rack is adequate to disperse the heat
dissipated in the rack (less than 2½% of maximum load or supply KW
rating, whichever the smaller), so long as the ambient (environment)
temperature does not exceed 35°C (95°F). Assisted ventilation for
the environment may be necessary in some locations to maintain
ambient temperature below 35°C.
3. 3. MOUNTING
See Figures 2. 1. 3 & 2. 1. 4 for fixing-hole dimensions.
Where racks are grouped, it will be found convenient to arrange them
in the correct sequence. Each Dimmer channel is numerically
identified, the numbers running in sequence throughout the
installation.
3. 4. CONNECTIONS
The channel identification numbering {see above) is the key for all
connections to lamp loads, associated Desk/Panel, etc., and also for
plotting cues and aiding maintenance.
7003
NOTE: Do not use high-voltage insulation testers to check wiring
associated with and connected to Dimmer Racks.
3. 4. 1. ACCESS TO TERMINALS IN THE RACK
Hinge open the fuse {or circuit-breaker) panel to gain access to
incoming-supply busbars and the terminals for lamp-load and
control-wiring connections. A removable panel is provided on
top of the rack to facilitate cable-entry.
Is sue 1
05301-032/Page 6 of 11
NOTE: Do not remove the panels covering the rest of the
cabinet-front except for access to Dimmer Modules for
maintenance.
3. 4. 2. INCOMING-SUPPLY CONNECTIONS
See Figure 2. 1. 2. on page 10.
3. 4. 2. 1. SUPPRESSOR UNIT
Rack(s) Isolator
: t;; {---1--:--:---.----+----1------'1'1--- - --1--~ } 3s~~~;e
I I N
L ____ J L ____ J
See Fig. 3. 4. 2. 1.
1- - - - - - - -1
1- I
L_ - - - ___ J
Suppressor Unit
Fig. 3.4. 2 .1
Note that the common terminal of the Suppressor Unit
capacitors is taken to the Neutral line. Local
electricity-authority regulations may require the
Suppressor Unit to be separately fused on each phase.
On single-phase systems (Phase, Neutral & Earth
only), two of the capacitors in the Suppressor Unit are
not used.
3. 4. 2. 2. RACKS
The busbars inside the fuse or circuit-breaker panel
are de signed and adequately rated for the appropriate
cable- sizes to be used.
In the case of 3-phase applications, the Dimmer
module input supplies are internally connected in phase
sequence (Red -A- to 1,4,7, etc; Yellow-B- to 2,5,8,
etc; Blue -C- to 3, 6, 9, etc.) unless otherwise specified
by the user. 3-phase racks may be used on singlephase supplies by shorting busbars B and C to A, and
connecting the phase- supply to A.
It is imperative to provide an adequate earth/ ground
conductor for the external wiring and connect it to the
earth/ ground bus bar E in the rack; do not rely on
earthing via the conduit or trunking of other conductors.
Is sue 1
7003
05301-032/Page 7 of 11
3. 4. 3. LOAD CONNECTIONS
'Load' and 'Neutral' terminals are numbered to correspond
with the Dimmer Modules. Since the control of output to load
involves waveform-switching of voltage, the two conductors to
each channel-load must be run as a pair of adjacent and equallength conductors; this will ensure that each conductor in the
pair carries equal and opposite current components. If a
patching panel or other form of load-selection unit is used,
divert the conductors as a pair to and from this unit. Lack of
care in this respect may result in strong induced fields tending
to vibrate the cable-trunking or radiate interference.
If armoured or conduited cables with adequate earthing of the
sheaths are not used, separate earth conductors are necessary •
and should be connected to earth-bar E in the racks.
3. 4. 4. 'CONTROL' CONNECTIONS: These are made primarily to the
associated Desk or Panel.
C
7101
3. 4. 4. 1.A-C SUPPLY CONNECTIONS: A suitable cable (Rank
Strand Electric Ref. 604) is a 3-conductor 2. 5 sq. mm.,
50/0. 25 (or, in the Imperial size, 0. 003 sq. inch,
70/0. 0b76) cable.
Note that in some installations, the associated desks
or panels may require to be fed separately from the
mains- supply. Where the desk- supply is specifically
to be taken from the rack, use the ABE terminals on
the 'Control' terminal block in the rack. Note that
terminal A is connected in the rack to the 'Blue' phase
{bar C) of a-c input supply to rack; terminal B is the
neutral line (bar N), and terminal Eis earth/ground
(bar E). Where the Desk requires more than one
supply from a group of racks, use the ABE terminals
of the second rack also.
On grouped racks, spare ABE terminals can be used
to power auxiliary circuits so long as the circuit-
rating of the 'Control' fuse is not exceeded.
3. 4. 4. 2. CONTROL-SIGNAL CONNECTIONS
Use terminals I to 10 (or 20) and Con the 'Control'
terminal block. Since the wiring has to Garry less
than 24V at a few mA, any suitable multi-conductor
cable can be used subject to local authority
regulations. A suitable cable (Rank Strand Electric
-Ref. 601) is a 12-conductor 0. 5 sq. mm., 16/0. 2 (or,
in the Imperial size, 0. 0006 sq. inch, 14/ 0. 0076)
PVC-insulated and sheathed cable, to be used one
cable per each 10 -channel rack and two cables per
each 20-channel rack; this cable has the advantage of
250V -grade insulation and does not have to be
segregated from mains -voltage conductors.
Issue 2
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05301-032/Page 8 of 11
3. 4. 5. OTHER INFORMATION
3. 4. 5. 1. When all connections have been made to a rack,
Connect each numbered terminal to the appropriate
numbered terminal (off the channel-lever potentiometer circuits) on the associated Desk or Panel;
connect the common return line to terminal C.
Using the above Ref. 601 cable, a consistent sequence
of connecting conductors to numbered terminals
(e. g., white, slate, brown, red, red/blue, red/white,
pink, orange, yellow, blue, violet, and black) will
facilitate channel identification for maintenance
purposes at a later date.
remove all cable-ends and other debris from the
terminal compartment; check all connections
carefully, especially to ensure that insulation is not
trapped in the pressure -pad terminals: close the
fuse (or circuit-breaker} panel.
3. 4. 5. 2. LAMP-LOADS: The Dimmers are designed to
control tungsten-load lamps of the same voltage
rating as the mains -supply. Each channel-dimmer
requires a minimum load of 60W for satisfactory
operation; hence smaller test-lamps or neon
indicators should not be used as entire loads.
The Dimmers can be used to control hot-cathode
fluorescent lamps but specified control equipment
must be used and the dimmer-ratings halved for
such applications.
The Dimmers can be used to feed low-voltage lamps
via step-down transformers providing a dummyload (resistive or preferably tungsten) of at least
lO0W rating is connected permanently across the
primary of the transformer, to protect the
transformer in the event of open-circuit of its
secondary load circuit.
3. 4. 5. 3. LOAD-LINE TERMINATIONS
These should preferably be to socket outlets numbered
to correspond with the channel identification numbers
and for the flexibility usually required of stage and
studio lighting, a standard socket outlet should be
adopted where possible.
Issue 2
In the United Kingdom, l 5Amp 3-pin BS546 outlets are
used in all installations except small installations
using dimmers rated at not more than lKW; in these
latter cases, 5A outlets are suitable. For high-voltage
loads requiring outlets of more than 15A rating,
suitably rated receptacles must be used.
7101
05301- 032/Page 9 of 11
For applications in countries other than the UK, local
practices or regulations must prevail.
3. 4. 5. 4. ASSOCIATED SOUND-SYSTEM INSTALLATIONS
Waveform switching, such as p:vovided by these
Dimmers, can reveal, in the form of spurious interference, previou,sly unsuspected earth-loops in the
associated sound- system installations. Careful
inspection of sound- system earthing, screening, etc.
may be necessary to remedy any earth-loops.
High-impedance microphone lines are also
susceptible to pick-up of switching 'noise' from lampcircuits; low impedance lines such as those used for
moving-coil microphones are most suitable,
especially if long audio cable-runs are necessary.
3. 4. 5. 5. OTHER CONNECTIONS
Do not connect or operate flash-boxes, similar pyro-
technic devices {or any appliance liable to absorb
surges of excessive power from the mains-supply)
from the Dimmer or associated load circuits; operate
such devices separately from the mains-supply, under
local {not remote) control by someone near the device
and with a direct view of it.
C
SETTING-UP INFORMATION
4.
NOTE: Only a qualified electrician familiar with the equipment should
undertake setting-up as detailed below. Switch off the rack supply before
removing the panels to gain access to the Dimmer Modules. Remember
that high-voltages are present at thyristor heat- sinks and associated
wiring/ components and take suitable precautions when measuring or testing
with the supply switched on.
4. 1. DIMMER MODULES
Connect a dynamometer voltmeter {or other instrument giving true RMS
voltage reading) across the load; use terminals Land Non the
Dimmer Module or use the Neutral line and the thyristor heat-sink
connected to terminal L.
Switch the channel on; set the associated Master Fader (if any) to full;
set the channel-lever to 1; adjust VRl on the Trigger Unit (see Fig.
2. 3) for an output voltage of about 5% of nominal supply voltage. Set the
channel-lever to 9; adjust VR2 for an output of about 96% of nominal
supply voltage. Repeat the two adjustments alternately till no further 4
adjustment is required.
7101
NOTE: The above data for setting up may need to be amended on
to suit individual lighting requirements; it is advisable to keep a
record of the finalised setting up {outputs against the two lever-
positions) for future maintenance purposes.
site
Issue 2
05301-032/Page 10 of 11
Fig. 2. 1. 1.
~
-i·
1=
Fuse
Panel
20-way 200- 250V Rack
an
-
(Note: The layout is similar in 10-way and other variations
of Racks)
Terminal
Blocks
Dimmer
Modules
Fig. 2. 1. 2. Terminal Compartment & Dimmer Modules
Issue 1 7003
05301-032/Page 11 of 11
Fig.2.2.
(View from top)
7003
Fig.2.3.
Issue 1
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