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Phase/AMP Series DPA1/DCPA1
SECTION IV - THEORY OF OPERATION
4-1.
FUNCTIONAL DESCRIPTION.
The primary function of the DPA-1 PHASE/AMP is the control of power to the load. This is accomplished by
controlling the point in each half cycle of input Voltage at which conduction can occur. See Figure 4-1. The
sine wave generator represents the 50 Hertz or 60 Hertz line Voltage. If the switch is closed at the moment
when the positive going half cycle of the input Voltage across points 1 and 2 is minimum (0 degrees), the
Voltage across load Z
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the positive going half cycle of the input Voltage across points 1 and 2 maximum (90 degrees), the Voltage
across load Z
will be as shown in detail (b) of Figure 4-1. If the switch is closed at a moment when the
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positive going half cycle of the input Voltage across points 1 and 2 somewhere between maximum (90
degrees) and minimum (180 degrees), say 170 degrees, the Voltage across load Z
c ) of Figure 4-1. A full half cycle of conduction corresponds to a conduction angle of 180 degrees, and when
no conduction occurs for the first 170 degrees of 10 degrees. See details (a) and ( c ), respectively, of Figure
4-1.
4-2.
If the switch in Figure 4-1 is rapidly turned on and off such that each positive half cycle of input Voltage
across points 1 and 2 has a conduction angle of 180 degrees, the Voltage across load Z
detail (a) of Figure 4-2. Similarly, if the switch is operated to provide a sequence of 90 degree conduction
angles, the Voltage across load Z
point, that as the conduction angle decreases the Voltage across load Z
Voltage across load Z
delivered to load Z
.
L
Figure 4-2 Comparison of Conduction Angles and Voltage Across Load
Document 9100030
will be as shown in detail (a) of figure 4-1. If the switch is closed at the moment when
Figure 4-1 Conduction Angle vs. Voltage Across Load
will be as shown in detail (b) of Figure 4-2. It should be obvious at this
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corresponds to controlling the current through load Z
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AMETEK HDR Power Systems
Theory of Operation
will be as shown in detail (
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will be as shown in
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will decrease. Controlling the
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and, therefore, the power
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