Page 19 - February 2022 Track N Times

TECHNICAL TRAINING

Warming Up With Watts Continued

Troubleshooting this circuit: Check Q 46, closed, check if KM583 is pulled in, check for 480V @ wires 464, 465,
466, if voltage is present, use amp clamp to measure current draw all three phases. If one or more phases do not
show a current draw, check for voltage at E46 heating element, if voltage is present all three phases, shut off and
lock out Q46, inspect the wiring at heater element visually, and check continuity of heater elements with an Ohm-
meter .

Three phase elements will partially operate and produce some heat even if only one element is good, but the heating
capacity will be diminished by one-third for each phase that is open.

Heat Tape:
The heat tape used on Loram machines is “self-regulating” meaning as the pipe temperature drops, its heat output
will increase. This means the current will go up as the temperature of the pipe goes down. The schematics list the
wattage of each the heat tape circuits. For example, the water car right side heat tape is listed at 1000 Watts. To
determine the current draw, multiply the listed wattage by .0083.
So, 1000 watts of heat tape would draw about 8.3 Amps. 1000 X .0083= 8.3 Amps. The best place to measure the
current is at the junction box where the tape run is connected. Shut off the associated circuit breaker, disassemble
the box, and ready the wires for measurement. Use caution when manipulating the wires, and double check the wire
nuts or connecting devices for good connections. When ready, you can restore power to the circuit and check the
current readings. Bear in mind these readings will vary depending on the pipe temperature, and the length of the
pipe. On a cold day, expect to see 50-80% of the breakers rating for an amp draw. Another method would be to use
a temperature gun or a FLIR camera. This may be difficult given most of the heat tape is covered by insulation.
When troubleshooting heater circuits, the amp clamp
is an indispensable tool. It tells you the rest of the sto-
ry. Get familiar with it’s use. If you need tips, contact a
technician whenever they are visiting your machine.
We’re always glad to help.

Page 17 FEBRUARY 2022