lev-co 13-12, Руководство пользователя

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b) A DC link which smooths the rectified output, usually by means of a large capacitor, and pro-
vides the control feedback to the primary voltage regulator.
c) A DC-to-AC inverter which converts the internal DC bus to the variable-frequency/variable volt-
age output power, usually by means of a high-frequency PWM (pulse-width-modulated) oscilla-
tor. The AC output is in fact a sinusoid synthesized from high-frequency pulses of variable width
and amplitude.
d) A controller which manages the output frequency and voltage as well as many other ancillary
functions.
Lev-co uses VFDs in one of three system architectures:

Type 1 – manually variable duct pressure with optional automatic start/stop

Type 2 – controlled duct pressure with optional automatic start/stop

Type 3 – controlled duct pressure and automatic start/stop with system-powered electrical
dampers.
Any of these basic architectures may be supplemented by options including fire detection and automatic
filter cleaning. These are described below.
1.3 List of Standard Models
Standard available models comprise the following:

Model 13-12 – Type 1 – VFD as a Contactor Replacement

Model 13-13 – Type 2 – VFD System with Constant Duct Pressure

Model 13-14 – Type 3 – Type 2 System with Controlled Electrical Dampers

Model 13-15 – Type 3 VFD System with Blast Gates

Model 13-16 – Enhanced Control System for Wet Collectors
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
Model 13-74 – Type 2 System with Vibra-Pulse Cleaning

Model 13-75 – Type 2 System with Shaker Motor Cleaning

Model 13-76 – Type 2 System with DC Sequenced Solenoids Cleaning

Model 13-77 – Type 2 System with AC Sequenced Solenoids Cleaning
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This model is not described in this Manual. It has its own User Guide, noted in the Reference Documents table.