Carbolite TVS Series - Manual (Page 12)

HZS, TVS
12
MF24 – 3.44
7.0 C IRCUIT D ETAILS
Safety Switches type A: A 2-pole Heater Switch is fitted directly in the element circuit in models
up to 16A rating. (Before mid-2000, up to 20A rating, 2 door switches were also fitted in this
position, in series with the Heater Switch.)
Safety Switch type B: A door switch is fitted into the contactor coil circuit. Above 16A a 1-pole
Heater Switch is fitted into the same circuit, in series.
7.1 Single Phase (example for control method A)
7.2 2- or 3-Phase with neutral
Each SSR is connected to a different phase. The control circuit is taken between L1 and N.
Safety switch B applies. 2-phase up to mid-2002: some models had door switch A.
If type F1 fuse is present, one per phase if fitted. If type F2 fuse is present, one is fitted; if type F3
fuse is present, one per phase is fitted.
Note that on 2- or 3-phase models there may be three separate neutrals taken to a common supply
terminal, depending on EMC filter requirements.
7.3 Independent Zones (control method C)
When this is ordered there are three independent thermocouples (instead of the four shown)
connected to the three controllers; the words “master” and “slave” may be replaced by “centre”
and “end”.
Instrument Switch
coil
slave
controller
thermocouples
overtemp.
controller
thermocouple
safety
switches B
SSR
heat
on
safety
switches A
F3
F1
F2
F3
N
L
PE
Filter (if fitted)
contactor
or relay
if fitted
master
controller
SSR
SSR slave
controller
F3
F3
main
ref.
slave
slave
elements
+
–
+
–
+
–
+
–