Electrical Connections - Dwyer Instruments 3000 Serie Manual De Instrucciones Y Operación

Bulletin B-33
page 4

ELECTRICAL CONNECTIONS

1. Cover
The amplifier-relay unit has an easy to remove housing. Remove the
three (3) screws as shown in Fig. 5 and slide the housing off. Make all
the electrical connections before reinstalling and refastening the
housing.
2. Conduit
Electrical access to the connection box portion of the relay housing is by
bottom opening for 3/4˝ conduit. Use of flexible conduit is recommended.
It should be supported from the panel or other suitable surface to prevent
the wiring system from exerting undue strain on the instrument. See Fig.
5.
Mounting Details
COVER MOUNTING SCREWS
SUPPORT CONDUIT
FROM PANEL
3. Terminal or Connection Board Layout
In Fig. 6,"Terminal Board", Section A contains the connections for the
load or slave relay actuated by the high or right set-point. This relay is a
double pole, double throw type. The two top connections are normally
closed, the two middle connections are normally open, and the bottom
connections are the common pair. The relay is in its normal or De-
Energized position when pressure is below the right hand set-point.
Section D is exactly the same as Section A except that its load or slave
relay is controlled by the low or left set-point. The De-Energized position
is below the left hand pointer set-point.
Section B contains the external connections to the holding coil circuit for
the high or right set-point relay and Section C contains similar
connections for the low or left set-point relay. The function and use of
these connections varies somewhat depending on the circuit style of the
instrument. See paragraphs 5 and 6 for details.
Section E contains the power connections for the control unit
transformer primary. The transformer in turn supplies reduced voltage
power for the LED, phototransistor, amplifier unit, and load relay pull in
and holding coils. Connections must always be made to this section in
order to put the unit in operation. Standard units are designed for 117
VAC input to the transformer. Special units are also available for other
voltages.
4-3/8 [111.13]
COVER PULL
OUT
FLEXIBLE CONDUIT
Fig. 5
Terminal Board
SECTION B
SECTION A
CAUTION: Do not apply electrical
current to terminals in sections B and C.
Separate Ground Wire attachment is provided for by a No. 6-32 screw
on the mounting bracket near the conduit opening. An additional ground
wire connection is located on the side of the gage body for use when the
amplifier-relay unit is mounted remotely.
Single Set-Point instruments are furnished with the right or high set-
point components and circuitry in place. These are connected to
Sections A and B of the terminal board. The left or low set-point
components are omitted.
4. Circuit Style
The Photohelic ® Switch/Gage is available with several factory installed
optional internal circuits. They are identified as to style by a label shown
in Fig. 7. This label is mounted prominently on the terminal board of each
instrument. The letter H denotes a circuit in which the relay can be made
to latch or remain energized after pressure increase to its set-point.
Circuit Label
CIRCUIT:
POWER SUPPLY:
CONTACT RATING:
The letter "L" denotes a circuit in which the relay can be made to latch or
remain de-energized after pressure decrease to its set-point. Two letters
are required to fully identify a dual set-point unit. Thus, circuit style HH,
which is standard, is a dual set-point circuit which has provisions for
latching on pressure increase to either set-point. Single relay units are
identified by the letters "SR" followed by "H" for the standard unit or "L"
for the special low latch unit. Units for use with other than standard 117
VAC will be so indicated on the label.
SECTION C
SECTION D
SECTION E
Fig. 6
Fig. 7