|• Offset Printing Machines|
|• Air – Cinditioning Plants|
|• General Laboratory Equiments.|
|• Signalling, Radars, Telecommunications.|
|• Industrial and Lighting Loads|
|• Domestic Load.|
|• Textiles Industries.|
|• Pharmaceutical Industries|
|• C.N.C Machines|
|• Medical Equipments|
|• Escalators and Elevators|
|• Cement Plants|
|• Oil Industries|
1KVA to 50 KVA
3KVA to 500 KVA
in balanced and unbalanced load
|160 – 270V
140 – 270V
90 – 260V
250 – 460V
150 – 460V
| 230V± 1%
or as desired
| 415V± 1%
or as desired
|Efficiency||Better than 95%||Better than 95%|
|Fully Automatic solid state glass
epoxy plug in control card
|Very low internal impedance|
|No effect on load power factor||High efficiency better than 95%|
|High reliability servo motor||Wide frequency range from 45Hz to 55HZ|
|No effect by any transient over voltage surges||Auto Manual Operation|
|Voltage limit indicators||Output Voltage adjustable|
|Input / Output Voltage monitoring||Accuracy ± 0.5% to ± 1% from no load to full load|
|Fast Correction speed (40 volts to 60 volts per sec.)||Surge rating 10 times the rated current upto 2 second.|
|3 times upto 60 seconds, twice upto five minute.||Environment: The quoted current rating apply to ambient temperature – 15°C to 45°C at higher temperature derate the output current by factors 50°C – 0.93, 53°C – 0.85,
60°C – 0.75 & 70°C – 0.50
|Cooling – Oil / Air cool.||110 volts output can also given|
|Under / Over Voltage Protection||Over Current Protection|
|Single Phase Preventer||Reverse Phase sequence protection for three phase unit|
|Earth fault protection|
|PRODUCT NAME||FULL NAME|
|Distribution Transformer rating 3KVA||EL / EOG / 4 – 74 with CS-1|
DC-DC converters are electronic devices used whenever we want to change DC electrical power efficiently from one voltage level to another. Theyre needed because unlike AC, DC cant simply be stepped up or down using a transformer. In many ways, a DC-DC converter is the DC equivalent of a transformer.
Typical applications of DC-DC converters are where 24V DC from a truck battery must be stepped down to 12V DC to operate a car radio, CB transceiver or mobile phone; where 12V DC from a car battery must be stepped down to 3V DC, to run a personal CD player; where 5V DC on a personal computer motherboard must be stepped down to 3V, 2V or less for one of the latest CPU chips; where the 340V DC obtained by rectifying 240V AC power must be stepped down to 5V, 12V and other DC voltages as part of a PC power supply; where 1.5V from a single cell must be stepped up to 5V or more, to operate electronic circuitry; where 6V or 9V DC must be stepped up to 500V DC or more, to provide an insulation testing voltage; where 12V DC must be stepped up to +/-40V or so, to run a car hifi amplifiers circuitry; or where 12V DC must be stepped up to 650V DC or so, as part of a DC-AC sinewave inverter.
In all of these applications, we want to change the DC energy from one voltage level to another, while wasting as little as possible in the process. In other words, we want to perform the conversion with the highest possible efficiency.
An important point to remember about all DC-DC converters is that like a transformer, they essentially just change the input energy into a different impedance level. So whatever the output voltage level, the output power all comes from the input; theres no energy manufactured inside the converter. Quite the contrary, in fact some is inevitably used up by the converter circuitry and components, in doing their job.
We can therefore represent the basic power flow in a converter with this equation:
Pin= pout+ Plosses
where Pin is the power fed into the converter, Pout is theoutput power and Plosses is the power wasted inside the converter.
Of course if we had a perfect converter, it would behave in the same way as a perfect transformer. There would be no losses, and Pout would be exactly the same as Pin. We could then say that:
Vin x Iin = Vout x Iout
or by re-arranging, we get:
Vout/Vin = In/Iout
In other words, if we step up the voltage we step down the current, and vice-versa.
Of course theres no such thing as a perfect DC-DC converter, just as there are no perfect transformers. So we need the concept of efficiency, where:
EFFICIENCY(%) = POUT/ PIN
Nowadays some types of converter achieve an efficiency of over 90%, using the latest components and circuit techniques. Most others achieve at least 80-85%, which as you can see compares very well with the efficiency of most standard AC transformers.
Many different types
There are many different types of DC-DC converter, each of which tends to be more suitable for some types of application than for others. For convenience they can be classified into various groups, however. For example some converters are only suitable for stepping down the voltage, while others are only suitable for stepping it up; a third group can be used for either.
Another important distinction is between converters which offer full dielectric isolation between their input and output circuits, and those which dont. Needless to say this can be very important for some applications, although it may not be important in many others.
In this data sheet were going to look briefly at each of the main types of DC-DC converter in current use, to give you a good overview. Well start first with those which dont offer input-output isolation, and then progress to those which do.
The non-isolating type of converter is generally used where the voltage needs to be stepped up or down by a relatively small ratio (say less than 4:1), and there is no problem with the the output and input having no dielectric isolation. Examples are 24V/12V voltage reducers, 5V/3V reducers and 1.5V/5V step-up converters.
There are five main types of converter in this non-isolating group, usually called the buck,boost,busk-boost, cuk and charge-pump converters. The buck converter is used for voltage step-down/reduction, while the boost converter is used for voltage step-up. The buck-boost and Cuk converters can be used for either step-down or step-up, but are essentially voltage polarity reversers or inverters as well. (The Cuk converter is named after its originator, Slobodan Cuk of Cal Tech university in California.)
The charge-pump converter is used for either voltage step-up or voltage inversion, but only in relatively low power applications.
The basic circuit configuration used in the buck converter is shown in Fig.1. As you can see there are only four main components: switching power MOSFET Q1, flywheel diode D1, inductor L and output filter capacitor C1. A control circuit (often a single IC) monitors the output voltage, and maintains it at the desired level by switching Q1 on and off at a fixed rate (the converters operating frequency), but with a varying duty cycle (the proportion of each switching period that Q1 is
|PRODUCT NAME||SPECIFICATION NUMBER|
|1 KVA to 60KVA||RDSO/PE/SPEC/TL/0023-2001 Rev.0 Amendment No.1|
The 1kVA UPS is designed to provide a conditioned power supply with battery backup for trackside ticketing machines within Indian Railways. The UPS uses MOSFET and IGBT technology to produce a regulated 230V, 50Hz output from a variable input supply. In the event of an input supply failure the UPS sources the output power from 48V DC batteries.
The system provides seamless changeover between mains and battery ‘stand-by’ supply and contains an active bypass, which activates during sustained overload and fault conditions, and a manual bypass for servicing purposes.
A battery charger supplies power to charge the batteries as well as to provide auxiliary power to the system controller.
The UPS contains a power factor correction (PFC) front-end rectifier to maintain a near unity power factor. The PFC stage establishes an intermediate dc link voltage which is pulse width modulated through a single-phase IGBT bridge and output filter to produce a regulated 230V, 50Hz single phase output.
The battery supply is boosted through a current fed push-pull (CFPP) converter and connects to the intermediate dc link voltage in parallel with the PFC output. This enables the CFPP to seamlessly take over supply of the power to the output inverter when the input AC supply is unavailable.
The UPS has an LCD and keypad for set point configuration, dynamic operating condition display and fault checking as well as indicator LEDs that show the current state of operation. In addition a USB port is provided on the front of the UPS for downloading of Fault Status data to a USB Memory stick.
|• IGBT Based inverter section|
|• Filtered AC Output with 1kVA capacity|
|• Input current limiting capability|
|• Input and Output Over Current protection|
|• Over temperature protection|
|• Output short-circuit protection (and lockout)|
|• Input Under Voltage & Over Voltage Protection|
|• DC link voltage monitoring|
|• Low losses & hence high efficiency operation|
|• Fused Input|
|• Modular design, hence easy maintenance|
|• Provision of fault memory recording for diagnosis & subsequent analysis
|• Provision of USB port for USB Memory Stick data downloading|
|• Auto-restart on fault elimination (dependent on fault type and frequency of
|Maximum Voltage||300V AC|
|Voltage Operating Range||140V – 280V AC 1 phase, 50 ± 3Hz|
|Rated Output VoltageI||: 230V AC ± 1%, 50 ± 0.5Hz|
|Output Current||: 4.5A|
|Output Power||: 1kVA @ 0.8pf|
|Overload maximum||125% load for 10 minutes|
|150% load for 1 minute|
|Efficiency||More than 90%|
|Operating Temp. Range||-5°C to 55°C|
|Cooling Medium||Fan forced air cooling|
|Dimension in mm
|468(L) x 200(D) x 275(H)|
|Protection||IP 20 for US Cubicle|
The 1kVA UPS unit has the following major functional elements: