Theatre Design & Technology - Fall 1990 - 71

the fact that it appears in the USITT journal (presumably a
technically competent magazine) under the "Engineering"
banner. The implication is that the USITT and its engineering
people have checked the facts in this article and approve of the
accuracy of the content. This is absolutely not the case. I suggest that had this article been reviewed by anyone of the
Engineering Commission members (or even outside engineers
in our industry), it would have been rejected as unsuitable for
publication in TD&Twithout serious editing of its content.
Nowhere does the article state that it is an "opinion"
piece, but its statements and conclusions seem to be little
more than opinions unsupported by fact. Furthermore, the
content of the article indicates a singular lack of understanding of dimmer selection criteria. Some of the "check list" specifications are so devoid of performance criteria that they read
as if the author had said:
A dimmer shall perform: (check one)
A. Excellently
B. Poorly
Some areas of the checklist-point six, for example-mix
completely unrelated areas of selection criteria, such as dimmer losses, choke losses and over-temperature reporting. Such
statements as "All modern dimmers give off about the same
amount of heat to the surrounding air" are patently false. The
heat loss in a dimmer is directly related to the efficiency of the
choke and SCR device, and may vary considerably from dimmer to dimmer.
Point nine of the checklist assumes that 19-inch rack
mounting is a desirable feature. For a fully integrated, UL-listed dimmer rack, the width of the rack is simply a non-issue.
Point 10 states "Hot patching has mostly been replaced
by electronic patching." This is completely untrue, since "hot
patching" OCCutS when a load is plugged into a live outlet,
whether or not a "patch panel" exists in the system.
Point 12 draws conclusions about the reliability of a dimming system which relate to the number of dimmers controlled by each control module in the dimmer rack. The
assertion that manufacturers "can cut some corners by sharing
more channels from a single circuit board" is absolutely false.
The reliability of modern dimming systems bears little relationship to the number of dimmers on a single control element. In fact, the entire dimming system is generally
dependent on only one element: the control console.
The bottom line is that the article contains many incorrect facts and will not help the specifier define a piece of
equipment that is well suited to his or her application.

Steven R. Terry

NEMA
Union Connector offers BRYANT Electric's Studio-Tech line
of NEMA wiring devices to the stage, studio and broadcast
industries. Another reason why we are the best single
source for electrical and wiring equipment.

The One Stop Connector Shop.

2P&G

Union Connector's own pin connectors have served the
industry with consistent quality and performance for over
sixty years. Our recognized reputation for superlative
service is true for the entire family of Union Connector
products. We are the source for electrical and wiring
equipment to the stage lighting and
TV/FilmNideo industries.
Call us.

New York, NY
Editors' Note: ALl articles appearing in TD&T are ''opinion''
pieces unless stated as being a board-approved commission 01'
institute report. We have recently completed the process of
appointing an associate editor for each of the ten special interest
areas of the Institute. Whenever possible, we wiLl utilize these
individuals as expert readers in determining the worthiness of a
particular manuscript for publication. But as a "volunteer" publication for a "volunteer" professional organization we are totally
dependent on the uncompensated contributions ofour readers for
material to print. ObvioUS9\ M/: Rosenthal-a working professional engineer who took the time to write and submit an article-has opinions which do not paraLlel those ofsome others in his
field. W'e, flS fllwflys, welcome flrtides find respollSes from those with
differing insights.

m
TD&T

1990 FAll

Table of Contents for the Digital Edition of Theatre Design & Technology - Fall 1990