Red-lion TCU User Manual download pdf (Page 65)

HEATER CURRENT MONITOR OPTION

This option allows monitoring of heater element current controlled by the

TCU via the main output OP1. The actual heater current is viewed in the lower

display. This is useful in determining how much the heater element has aged,

if the element open circuited or if the element has a ground fault. A Heater

Break Alarm can be programmed to signal the event before process damage

occurs (See Alarm Action, page 29). Normally, the heater current alarm value

is set for 10-20% below the actual heater current value. This allows for line

voltage variations and a small amount of heater element oxidation (aging).

The Heater Current Monitor is for single phase power monitoring. For

3-phase heating systems, Red Lion Controls Model IMH (5 ampere Current

Transformer Indicator) can be used to monitor individual line phases.

Example: A 50:0.1 current transformer is used. The actual observed h eater

current is 38 amperes. The heater fault alarm is used and set to trigger at

32.0 amperes (38A * 85%). Placing the current transformer in the ground

(neutral) lead allows for heater ground fault detection. The following lists

the parameters for configuring the Heater Current Monitor with Alarm

fault detection.

HCur - 50.0 Set full scale heater current equal to current

transformer rating

ACt1 - HCur Program Alarm #1 for heater fault action

AL1 - 32.0 Set heater current alarm for 32.0 amperes

Figure 27, Heater Current Monitor Diagram

1 2 ... 60 61 62 63 64 65 66 67 68 69 70 ... 103 104

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Red-lion TCU User Manual Page 65