17
O&M Manual
Rev-D (11/19)
Part 4 – Electrical Installation
4.1
General
The Q46 is powered in one of two ways, depending on the version purchased. The 12-24 VDC
powered analyzer requires a customer supplied DC power supply. The 90-260 VAC version
requires line power. Please verify the type of unit before connecting any power.
WARNING: Do not connect AC line power to the DC version. Severe damage will result.
Important Notes:
1.
Use wiring practices that conform to national, state and local electrical codes. For proper
safety as well as stable measuring performance, it is important that the earth ground
connection be made to a solid ground point on TB7. The AC power supply in the
transmitter contains a single 630mA slo-blo fuse (Wickmann/Littlefuse #372-0630). The
fuse
F1
is located adjacent to
TB7
and is easily replaceable.
2.
Do NOT run sensor cables or instrument 4-20 mA output wiring in the same conduit that
contains AC power wiring. AC power wiring should be run in a dedicated conduit to prevent
electrical noise from coupling with the instrumentation signals.
3.
This analyzer must be installed by specifically trained personnel in accordance with
relevant local codes and instructions contained in this operating manual. Observe the
analyzer's technical specifications and input ratings. Proper electrical disconnection means
must be provided prior to the electrical power connected to this instrument, such as a circuit
breaker - rated 250 VAC, 2 A minimum. If one line of the line power mains is not neutral,
use a double-pole mains switch to disconnect the analyzer.
4.
Repeated problems with lightning strikes damaging sensitive instrumentation are often
attributed to poorly bonded earth grounds in the instrument power source. The protection
schemes incorporated into this analyzer cannot operate to maximum efficiency unless the
ground connection is at its’ absolute lowest impedance.
There is no standard ground resistance universally recognized. Many agencies recommend a
ground resistance value of 5 ohms or less. The NEC recommends an impedance to ground of
less than 25 ohms, and less than 5 ohms where sensitive equipment is installed. Power sources
feeding sensitive instruments like the Q46H/79PR should have the lowest possible impedance to
ground
.
4.2
Electrical Connections
Verify the power supply requirement before installing. Also verify that power is fully disconnected
before attempting to wire.
Q46 systems are supplied with 5 cable gland fittings for sealing cable entries.
Connect appropriate power to the matching designations on terminal strip
TB7
.
