Frequency Converter

The Frequency Converter is designed to supply 115V, 400Hz AC supply from 220V/115V, 50Hz AC source by static conversion method. This equipment shall provide 115V,400Hz, 250VA stable supply. The equipment design employs a PWM technique has very high efficiency and a fast response. The input AC supply is converted to DC voltage via a full bridge rectifier circuit. This DC voltage is converted to AC supply of desired frequency via the full bridge inverter. Varying the duty cycle of the switching transistors controls the output voltage. The system has many operation benefits such as : Good output voltage regulation Fast dynamic response. Higher system efficiency over total output power range. Higher reliability. Reduction in overall system size and weight.

Trans Rectifier Unit

The Transformer Rectifier Unit is designed to supply 24VDC unregulated supply from 415V AC, 50Hz, 3 Phase. The voltage will be such to adopt cable drops during load. The equipment design employs a step-down transformer and rectifier circuit. The I/P supply is step down to 24VDC by using a step down transformer. The Trans Rectifier Unit is design to provide the following Technical Specification.

1) Input : 415V AC ±5%, 3 Phase,3 Wire(395VAC-435VAC).

2) Input Frequency : 50Hz ± 2.5 %

 3) Output Voltage : 24VDC Nominal unregulated (three phase rectified) at I/P 415 VAC, O/P 27VDC. If the I/P supply fails then the Battery is connected Automatically, Battery Voltage (20VDC-24VDC)

 4) Output Current Limiting : Internally fuse link of suitable rating is provided For 1KW=50A & 2KW=80A(GE Make)

 5) Battery Charger : (To charge two batteries of 12V DC/40AH in series at 4 Amp).Constant current, short circuit protection (27V/4Amp) charge with reverse Battery Protection. Separate terminals are provided for charging the batteries.

Auto Change Over Scheme

The Auto Change Over Scheme (ACOS) is intended to use as a power selector switch to ensure the continuity of the electrical supply to User. The equipment design provides momentarily signal to make and break MCCB's by using relay modules. The Auto Change Over Scheme is design to provide the following Technical Specification.

Ventilation Control Panel

The Ventilation Control Panel is designed to monitor the Air over heating, presence of pressure, fan on, HE true flow S/W on indication of the HE-3, HE-7, HE-5 and HE-85.

18.5KW Starter

The starter is design to provide following protection. Single phasing protection, over current protection, over/under voltage protection, no load protection, short circuit protection, unbalance current protection, and earth fault protection for 18.5 KW starter.

875KW Mobile Battery Charging Rectifier

The Mobile Battery Charging Rectifier is design to provide the following technical specifications.

1) INPUT Voltage : 415V AC, 3Phase, four wire, 50Hz (± 10 to 15 %)

 2) OUTPUT Voltage : 175V DC to 380V DC variable in Auto/Manual Mode

 3) OUTPUT Current : 230 Amps DC to 2500 Amps DC variable

 4) Voltage regulation : ± 1 % against input and O/P load variations and temperature variations 35 to 50 degrees.

 5) Ripple content : 3 % in battery current.

 6) Over load : As per IEC 146

 7) Over current voltage: up to 455V DC

 8) Range of O/P for constant current 2500Amp : 175 to 380V DC

 9) Efficiency of Converter AC to DC : 95% Min at min I/P voltage and maximum O/P voltage current

PROTECTION

 1) Incoming ACB/MCCB with trips for overload.

 2) EMI/EMC filter at I/P

 3) Output over voltage tripping.

 4) Fuses at input with fuse

 5) The system shall be independent of phase sequence reversal

 6) System to be protected against under and over voltage at I/P

 7) Short circuit protection and over load trip by electronic circuit.

 8) High temperature of semi conductor sense and trip

 9) Failure of cooling fan with inter lock

 INDICATION

 The panel have a digital display of all parameters as follows

 1) Input current

 2) Output current

 3) Input voltage

 4) Output voltage

 5) Ampere hour at output

 6) Indication of faults and fuse failure

7) Alarm reset

 The system parameters are set by a key board for voltage/current and an optional feature to set current/voltage/change over period etc. Controls were digital.

3 Phase Static Frequency converter

The 3 Phase Frequency Converter 60Hz/400Hz is design to provide the following Technical Specification. 1) Rating : 20 KW

2) Input Voltage : 195 to 365 V DC

 3) Output Voltage : 120 V AC (± 1%) Line to Line 3  Phase (Suitable for 100% unbalanced load) Setting range ±5 V

 4) Output frequency : 60Hz (± 0.1 Hz)

 5) Output waveform : Sinusoidal

 6) Total Harmonic Distortion : < 2 %

 7) Protections :

         a) Over voltage : In case of Voltage regulation failure, the inverter should shut down

         b) Short circuit : The inverter should shut down without any failure of component.

         c) Over Temperature : In case the heat sink exceeds 900C the inverter should shut down. A visual indication is given at 850C before the inverter is to be shut down at 900C.

         d) Frequency Deviation : The inverter should shut down in case the output frequency drifts beyond the permissible limit of ± 5 %. To be confirmed by simulation.

 8) Power Factor : 0.9

 9) Over load :

         a) 150 % for one minute

         b) 125 % for ten minute

 10) Class of insulation : H class

 11) Control and Indication :

         a) Inverter ON/OFF

         b) Emergency operation (to switch off)

         c) Voltmeter to indicate phase to phase voltages

         d) Ammeter to measure current in all three phase

         e) Frequency Indication

 12) RS 232 C Port : Serial communication for monitoring / control of input Voltage, Current and Output Voltage, Current, Frequency ( Including Software).