9424200996 70-3
BE1-11m Thermal Curve (49TC) Test
Step 3: Prepare to monitor the 49TC function operation. Operation can be verified by monitoring OUT1
(Tripped) and OUT2 (Overloaded). See Figure 70-1.
Step 4: Connect a three-phase 60 Hz current source to terminals D1 and D2 (IA), D3 and D4 (IB), and
D5 and D6 (IC).
Step 5: The following calculations are referenced in this test procedure.
The Overload Pickup Current is calculated in Equation 70-1.
= × × = 1 × 1 × 2 = 2
Equation 70-1. Overload Pickup Current
Where:
S = Overload Scaler
SF = Scale Factor
FLA = Full Load Amps
The Equivalent Thermal Current is calculated in Equation 70-2. Assume a three-phase
balanced current of 10 A.
=
1 +
= 10
1 + 0
= 10
Equation 70-2. Equivalent Thermal Current
Where:
I
eq
= equivalent thermal current in pickup (unit of thermal pickup current)
I = maximum phase current in pickup
I
1
= positive-sequence fundamental component of current in pickup
I
2
= negative-sequence fundamental component of current in pickup
k = constant used to determine additional heating from negative-sequence
current in pickup
The Standard Curve Timing is calculated in Equation 70-3.
= × 88.744132 ×
1
= 10 × 88.744132 ×
10
2
10
2
1
= 36.22
Equation 70-3. Standard Curve Timing
Where:
t = Operating Time
I
eq
= Equivalent Thermal Current
TD
= Time Dial
I
tpu
= Overload Pickup Current
Step 6: Apply 1.9 Aac three-phase current. Slowly raise the current until OUT2 (Overloaded) closes and
record the pickup. Slowly lower the current until OUT2 (Overloaded) opens and record the
dropout. Remove three-phase current and wait until thermal capacity falls to 0% before
proceeding. The thermal capacity can be monitored at Metering > Motor > Motor Meter on the
front-panel display.
Step 7: Simulate motor starting by applying 10 Aac, three-phase current. Verify that OUT2 (Overloaded)
closes indicating an overloaded condition. Verify that OUT4 (Starting) closes. Measure and
record the time from when current is applied until OUT1 (Tripped) closes and the thermal
capacity reaches 100%. The expected timing is 36.22 seconds per Equation 70-3. The thermal
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