Course 1-1: Pre-Test

How many cycles are shown in the following diagram?

How many cycles are shown in the following diagram?

Click on the the image that has 9 cycles and click the “Check” button.

Click on the the image that has 10 cycles and click the “Check” button.

Use the following formulas and your calculator to figure out the expected time-to-trip in seconds if the relay uses the Nominal System Frequency as a reference? (Enter 3 decimal places, for example 1.234)

Nominal System Frequency [NSF] = 50 Hz

Relay Setting (Cycles) = 10 cycles

Relay Reference = NSF

Test-Set Reference = NSF

Generated Frequency (Hz) [GF] = 56.3 Hz

Use the following formulas and your calculator to figure out the expected time-to-trip in cycles if the relay uses the Generated Frequency as its reference and your test-set uses the Nominal System Frequency as its reference? (Enter 3 decimal places, for example 1.234)

Nominal System Frequency [NSF] = 50 Hz

Relay Setting (Cycles) = 45 cycles

Relay Reference = GF

Test-Set Reference = NSF

Generated Frequency (Hz) [GF] = 47.3 Hz

Use the following formulas and your calculator to figure out the expected time-to-trip in seconds if the relay uses the Generated Frequency as its reference? (Enter 3 decimal places, for example 1.234)

Nominal System Frequency [NSF] = 60 Hz

Relay Setting (Cycles) = 1800 cycles

Relay Reference = GF

Test-Set Reference = GF

Generated Frequency (Hz) [GF] = 61.6 Hz

Use the following formulas and your calculator to figure out the expected time-to-trip in seconds if the relay uses the Generated Frequency as its reference? (Enter 3 decimal places, for example 1.234)

Nominal System Frequency [NSF] = 50 Hz

Relay Setting (Cycles) = 1800 cycles

Relay Reference = GF

Test-Set Reference = GF

Generated Frequency (Hz) [GF] = 51.6 Hz

Use the following formulas and your calculator to figure out the expected time-to-trip in seconds if the relay uses the Nominal System Frequency as a reference? (Enter 3 decimal places, for example 1.234)

Nominal System Frequency [NSF] = 60 Hz

Relay Setting (Cycles) = 45 cycles

Relay Reference = NSF

Test-Set Reference = NSF

Generated Frequency (Hz) [GF] = 57.3 Hz

Use the following formulas and your calculator to figure out the expected time-to-trip in cycles if the relay uses the Nominal System Frequency as its reference and your test-set uses the Generated Frequency as its reference? (Enter 3 decimal places, for example 1.234)

Nominal System Frequency [NSF] = 60 Hz

Relay Setting (Cycles) = 600 cycles

Relay Reference = NSF

Test-Set Reference = GF

Generated Frequency (Hz) [GF] = 61.7 Hz

Is this an A-B-C or A-C-B 3-phase system?

Is this an A-B-C or A-C-B 3-phase system?

You have performed two timing tests to to find out what reference the test-set’s cycle timer uses.

• Test #1: The relay operates in 3.96 seconds and the test-set timer displays 225.72 cycles at 57 Hz.
• Test #2: The relay operates in 3.94 seconds and the test set displays 220.8 cycles at 56 Hz.

Use the following formulas and your calculator to figure out what reference the test-set uses to count cycles?

You want to find out what reference the relay’s cycle timer uses and perform two timing tests.

• Test #1: The relay operates in 2.01 seconds at 57 Hz.
• Test #2: The relay operates in 2.01 seconds at 56 Hz.

Use the following formulas and your calculator to figure out what reference the relay uses to count cycles?