Altronic 6715 D, Руководство пользователя, Страница: 15 / 20

6715D/Rev. Jul.2020 Page 15 Altronic Research Inc.
SECTION IV
THEORY OF OPERATION
4-1. General. The Model 6715D contains a 50 ohm non-reactive resistor assembly which is
cooled by forced air supplied by a centrifugal blower assembly. Control of the blower and
of the transmitter interlock circuit is accomplished with a single rocker switch and five
thermal switches.
4-2. Control Circuits. Control Power is derived from a Control Transformer that is fed by a 3
ampere circuit breaker. The Control Transformer provides power for the operation of the
Transmitter Interlock Circuit and Blower Control. The blower assembly is powered by a
separate breaker that can vary in ampacity depending on the current draw of the Blower
Assembly (see Specifications).
Blower Control Circuit: Three thermal switches and one rocker switch are connected to AC
Control Line 1. The thermal switches are Single Pole, Normally Open, and close at a
specific temperature (as detailed in the schematics) and connect to Blower Contactor
“RYI” terminal 0, as does the SPST rocker switch. Blower contactor “RY1” terminal 1,
connects to AC Control Line 2. The blower indicator lamp is connected in parallel with the
contactor coil.
Transmitter Interlock Circuit: Two thermal switches are connected in series from Control Line 1
to Interlock Relay “RY2” terminal 13. These thermal switches are Single Pole, Normally
Closed, and open at a specified temperature (as detailed in the schematics). The overheat
lamp is connected from Line 1 to interlock relay “RY2” Terminal 13. Interlock relay
“RY2” terminal 14 is connected to Control Line 2.
Interlock relay (RY2) terminals 5 & 6 are paralleled and are connected to interlock terminal strip
(TB1)-1. Interlock relay (RY2) terminals 9 & 10 are paralleled and are connected to
interlock terminal strip (TB1) terminal 2. This terminal pair will be closed when there is
AC main power to the load.
When sold with two sets of Normally Closed terminals at TB1 interlock relay (RY2) terminals 7 &
8 are paralleled and are connected to interlock terminal strip (TB1) terminal 4. Interlock
relay terminals 11 & 12 are paralleled and are connected to interlock terminal strip (TB1)
terminal 3. This terminal pair will be closed when AC power is supplied to the load.
When sold with one set of Normally Closed terminals and one set of Normally Open terminals at
TB1 interlock relay (RY2) terminals 3 & 4 are paralleled and are connected to interlock
terminal strip (TB1) terminal 4. Interlock relay terminals 11 & 12 are paralleled and are
connected to interlock terminal strip (TB1) terminal 3. This terminal pair will be open
when AC power is supplied to the load.