User Manual
2253i / 2253iX
AMETEK
California Instruments
92
5. Principle of Operation
5.1 Overall Description
The 2253i/iX models share a common architecture based on single 750VA power amplifier module
assembly (P/N 6005-400-1). Power to all amplifier modules is derived from a power factor corrected
bias supply PFC module (P/N 6005-707-1 and 6005-709-1). The PFC assembly upconverts the AC
input through a high frequency AC transformer that provides full isolation from the line and also
accommodates a universal input range from 115V L-N to 230V L-N ac nominal.
The front of the unit houses the digital controller and waveform generator (P/N 6005-703-1) as well as
the keyboard display assembly (P/N 6005-703-2). The entire controller front panel assembly (P/N
6005-403-1) can be removed from the main chassis if needed.
5.2 Amplifier Assemblies
The Phase A Amplifier Assembly (P/N 6005-400-1) is located on the right hand side of the chassis.
The Phase B amplifier assembly is installed in the center of the chassis and the Phase C amplifier is
located on the left hand side (when facing front of the unit). All amplifier assemblies are identical and
their positions can be swapped although there is no reason to do so.
The power module contains two independent direct-coupled half-bridge amplifiers. The half bridges
may be operated independently (in LO RANGE only, 0 to 150 vac) for two-phase operation but this
capability is not used in the 2253i/iX where both half bridges are used for one phase operation only.
Each half bridge is rated for 375 VA. One output is taken from OUTPUT LEFT to HV COM OUT and
the other output is taken from OUTPUT RIGHT to HV COM OUT.
The half bridges may be operated together for a total of 750 VA. The LEFT amplifier will be the master
amplifier and it will drive the RIGHT amplifier.
In LO RANGE the OUTPUT LEFT and RIGHT lines are tied together and drive the load with respect to
HV COM OUT.
In HI RANGE (0 to 300 vac) the OUTPUT LEFT and RIGHT lines are separated and the output is
taken from OUTPUT LEFT with respect to OUTPUT RIGHT. HV COM OUT is not used in HI RANGE.
5.3 PFC and Rectifier Assembly
The PFC and Rectifier Assembly (P/N 6005-707-1 and 6005-709-1) consists of two modules mounted
back to back and connected by a set of heatsinks. It is located on the left hand front side of the
chassis below the auxiliary DC bias supply. This module generates six regulated DC buses that
provide power to the three amplifier modules.
5.4 EMI Filter Assembly
The EMI Filter Assembly (P/N 4005-710-1) is located in the rear left corner of the chassis. It filters the
AC input line and distributes AC power to the input PFC and rectifier assembly and the auxiliary bias
DC supply.
5.5 Auxiliary DC bias Supply
An auxiliary bias DC Supply (P/N 6005-711-1) is located on the left side of the chassis above the PFC
input assembly.
