Overall Description; Oscillator Assembly - Ametek i Series User Manual

User Manual

5.2 Overall Description

Three or single phase input power is routed in from the back panel through an EMI filter and the
circuit breaker to the input bridge rectifier. The DC output from the bridge rectifier is smoothed
by a small amount of capacitance in order to keep the input power factor as high as possible.
This DC output supplies the converter on the DC power board.
The DC converter turns the unregulated rectified AC into a smoothed, isolated, tightly regulated
DC supply. Also mounted on the DC power board is the auxiliary power supply. The auxiliary
power supply creates low voltages to operate the control logic board, the oscillator board, the AC
power board, and the fan. The output of the DC converter is fed to two large electrolytic
capacitors on the I/O board. These capacitors also provide holdover storage energy to ride
through line dropouts.
The AC power board takes the DC input and puts out isolated, direct coupled, AC power.
The DC bus is regulated at 250 volts for the 135/150 VAC output and 500 volts for the 270/300
VAC output.
The oscillator assembly generates the reference waveforms and provides frequency, amplitude,
and impedance control. The current limit board, in conjunction with the oscillator board, provides
the current limit function.
The assemblies are described in more detail in the following paragraphs. Refer to Figure 5-1 for
an overall block diagram.

5.3 Oscillator Assembly

The oscillator assembly consists of three printed circuit board assemblies connected by a ribbon
cable. The oscillator generates the sine wave signal setting the frequency, amplitude and current
limit level. It also senses the output voltage to provide closed loop control of the output.
5.3.1 CPU/Phase A Board
This board assembly, A7, consists of the components for the DSP, generating the input signal for
the power amplifier, programmable impedance and all of the memory. In addition, the waveform
board contains the circuits for all measurements and remote sense. The clock and lock circuit
for 3-phase operation is also on this board assembly.
This board has several jumpers that are used to enable various option. Refer to the following
table for the options. See Figure 5-2.
Standard, CLK & LK
Master
CLK & LK Slave
102
JUMPER ( += in, - = out)
W3 W4 W5
- + +
+ - -
W6 W7 W8
- + -
+ - +
i Series / iX Series
W9
+
-