In order to compare the volume, weight, and power consumption of solid-state and electromechanical switches from a bottom-up perspective, Tables 1 and 2 provide the weight, volume, and power consumption of commercial electromechanical relays and circuit breakers, each from multiple suppliers. These tables include the external dimensions, weight, and power consumption of five 28V, 25A relays and five 28V, 25A circuit breakers. In addition, they also include the calculated PC board real estate and the volume of these components, as well as the calculated average values of these parameters.

For relays and circuit breakers, the average real estate per channel is 1.22 square inches, which is 1.56+0.66. Assuming that relays and circuit breakers account for 60% of the total area of the PC board, the total real estate of each channel is 2.22/0.6=3.7 square inches. Use an average circuit breaker height of 2.34 inches. Assuming a PC board thickness of 0.093 ", a top side gap of 0.02, and a back gap of 0.25" (similar to comparable SSPC board components), the total assembly height of the relay/circuit breaker board component is 2.34+0.02+0.093+0.25=2.7 inches. The total volume of a channel is (3.7) * (2.7)=9.99 cu. Unit volume output power=(28) * (25)/(9.99)=70.1 W/cu.

For the 16 channel SSPC board component, the board size is 9.2 X 6.3 inches, the maximum component height is 0.54 inches, the PC board thickness is 0.093 inches, the back gap is 0.25 inches, and the total height is 0.54+0.093+0.25=0.883 inches. The total volume of 16 channels is 9.2 X 6.3 X 0.883=51.18 cu. In there. This is equivalent to 51.18/16=3.20 cu. In there. Each channel. For a 25 ampere channel, the output power per unit volume is (28) * (25)/3.20=219 W/cu. The weight of a typical 9.2 X 6.3, 0.093 inch thick bare PC board is 0.55 pounds. For this type of board, the weight per unit area is. 55/(9.2) * (6.3))=. 0095 pounds per square inch. For a relay+circuit breaker channel, the total real estate of each channel is 3.7 square inches, so the weight of the PC board for each channel is 0.035 pounds. The total relay+circuit breaker weight for each channel is 0.14+0.08+0.035=0.255 lbs. The output power of each weight is 2745 W/lb. The weight of a typical 16 channel SSPC board component is 1.8 pounds. For a 28 volt, 25 ampere SSPC channel, the output power per unit weight is 6222 W/lb.

The contact dissipation data for relay # 1, relay # 4, and circuit breaker # 1 are not available and therefore not included in the average dissipation calculation.

a. For relays and circuit breakers, the average printed circuit board area (square inches) and volume (cubic inches) are the averages of two different methods:

One kind. Using the first method, calculate the average printed circuit board area as the average printed circuit board area of five relays or circuit breakers. Similarly, calculate the average volume as the average volume of five relays or circuit breakers.

b. Using the second method, calculate the average PC board space as the average width of five relays or circuit breakers multiplied by the average depth. Similarly, calculate the average volume