Molded Case Circuit Breaker Tester AMCCB250

The AMCCB-250 is a programmable, high-current source designed specifically for testing molded-case circuit breakers as well as thermal, magnetic, or solid-state overload motor-protection relays.

Built-in Timer

The AMCCB-250’s built-in timer can test the time-delay characteristics of protection relays and molded-case circuit breakers. Once the test is initiated, the current source and the timer are automatically turned on at the next zero-crossing point of the AC. The timer stops when the AMCCB-250 input detects a change in the dry contact or voltage input, or detects the removal of the test current. The test results are then displayed in milliseconds and fractions of cycle(s) on the unit’s back-lit LCD screen (20 characters by 4 lines).

External Current Input

The AMCCB-250 also provides an external current input (0 – 10 A). Both internal and external current source readings can be viewed at the same time.

Current Source

The AMCCB-250 has 4 current-source outputs (5 A @ 120 Vac, 25 A @ 24 Vac, 120 A @ 6 Vac, 250 A @ 3 Vac) that conduct the test current through the high-impedance load circuits. Each current source can tolerate short duration over-loads up to 4 times the rated current (1000 A max). This feature is used for testing the instantaneous trip element of molded-case circuit breakers. When using this feature, the selected test current is displayed on the LCD screen. When the MCCB-250 is used as a current source, the current flow time (the current-on period) is displayed on the LCD screen.

AMCCB-250 Output Current and Duration Table

Current	On time	Off time
100% (1x)	30 minutes	30 minutes
200% (2x)	3 minutes	5 minutes
300% (3x)	30 seconds	4 minutes
400% (4x)	4 seconds	7 minutes

Complete specifications table

Type	250 Ampere current source
Physical specifications	17"W x 12K"H x 10K"D (42.6 cm x 32cm x 27 cm). Weight: 46 lbs (21 kg)
Input power	100 - 120 Vac or 200 - 240 Vac (factory pre-set), 50/60 Hz
Output currents	0 - 5 A @ 120 Vac max; 0 - 25 A @ 24 Vac max; 0 - 120 A @ 6 Vac max; 0 - 250 A @ 3 Vac max
Internal current meter	100 mA - 1000 A; Accuracy: 1% of reading ±20mA
Measurement method	Isolated CT
External meter range	10 mA - 10 A; Accuracy: 1% of reading, ±2mA
Timer reading range	1ms - 2 hours; Accuracy: 0.1% of reading ±1ms
Timer stop inputs	Voltage input (24V - 300V, DC or peak AC), dry contact input, or removal of primary current
Display	Back-lit LCD Screen (20 characters by 4 lines); viewable in bright sunlight and low-light levels
Computer interface	RS-232C port for factory calibration and diagnostics
Safety	Designed to meet IEC61010 (1995), UL61010A-1, CSA-C22.2 standards
Environment	Operating: -10°C to +50°C (+15°F to +122°F); Storage: -30°C to +70°C (-22°F to +158°F)
Humidity	90% RH @ 40°C (104°F) non-condensing
Altitude	2,000 m (6,562 ft) to full safety specifications
Cables	Power cord, ground cable, 10-foot #2 AWG test leads
Options	Transportation case
Warranty	1 year on parts and labor