DC Supply NV725
Learning Material Ver 1.1
141-B, Electronic Complex, Pardesipura, Indore- 452010 India Tel.: 91-731- 4211500 Email:
[email protected] Toll free: 1800-103-5050
NV725 DC Supply NV725 Table of Contents 1. Introduction
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2. Features
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3. Technical Specifications
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4. Theory
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5. Procedure
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6. Safety Precautions
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7. Warranty
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8. List of Accessories
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NV725 Introduction NV725 Fixed and Variable DC Supply is a most important product, which have an important role for practical performance and it is most widely used in laboratory. The DC power supply is used to generate either a constant voltage or a constant current. That is, it may be used as either a DC voltage source or a DC current source. You will be using it primarily as a voltage source. Recall that DC is an acronym for direct current. DC means constant with respect to time. The DC power supply has two output terminals. The one for fixed DC and another for variable DC supply, which allows the power supply to produce between 0 and 180 Volts and has a maximum current capacity of 0-10 amps. The DC voltage produced by the power supply is controlled by the knob labeled voltage. Voltage limiting allows the power supply to be set such that it will not generate more voltage than desired. This can be useful as a safety feature, preventing electrocution due to accidental contact with terminals. In addition, voltage limiting can prevent damage to equipment and parts which may be unable to handle excessive voltage.
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NV725 Features
Exclusive and rugged designed panel
Stand alone operation
Designed by considering all the safety precautions
High quality meters
Learning Material CD
2 Year Warranty
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NV725 Technical Specifications Input AC Voltage
:
230V ±10%, 50Hz
Output DC Voltage
:
0-180V ±10%
Fixed
:
180V
Variable
:
0-180V
Rating
:
2KVA, 50Hz
Primary
:
230V
Secondary
:
150V/150V
Auto Transformer
:
270V, 10A
Bridge Rectifier
:
20A
Capacitor
:
470 MFD, 400V
Ammeter
:
0-10Amp
Voltmeter
:
0-300V
MCB
:
10A
Transformer:
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NV725 Theory DC supply has assembled with various components such as:
Transformer : Transformer is a static device which transfers the electrical energy one circuit to another circuit without change of frequency. It works on the principle of electromagnetic induction. We can use the transformer as step up, step down and isolation purpose. Here transformer used for isolation. 2KVA Transformer
Figure 1 Transformer winding is single piece of usually solid copper wire with an insulation coating, sometimes referred to as varnish. It is wound on a transformer core of magnetic material. The iron core or lamination assembly of a transformer. In our applications this core will either be made of thin sheets of iron alloy material stacked together or it might be a solid core made from powdered iron pressed together with an adhesive binding material, which could be of a number of physical shapes including a circle or toroid.
Autotransformer : This is the simplest and cheapest way to decrease or increase an AC voltage without the heat loss produced by resistive devices. Because there is only one winding and there is no isolation from the input source.
(A)
(B) (C) Auto Transformer Figure 2 This is a variable autotransformer, sometimes referred to as a autotransformer which is a trade name. Instead of a fixed tap it has a wiper made of a soft conductive material. The wiper is connected by insulated material to a knob that is used to adjust the output voltage. This is the winding of an autotransformer. Notice that the surface of the winding has been machined so that the wiper can make electrical contact. Since these devices are best made round to accommodate the circular motion of the wiper, the iron core is made from a mixture of powdered iron and a binding agent.
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NV725
Bridge Rectifier :
Bridge Rectifier Figure 3 Typical bridge rectifier package that is just over an inch square and about 3/8" thick with 1/4" push on tabs. It has a metal surface on the bottom for heat transfer and should be mounted on a metal surface to act as a heat sink. The center hole will accommodate a standard 10-32 or comparable metric screw for mounting. These size packages are available in ratings up to 40 amperes. Diodes and bridges are rated in current and peak inverse voltage (PIV). PIV is the term used to say that the diode or rectifier pack will withstand a reverse polarity voltage of a given level. A good rule of thumb is to use a device rated at a PIV of twice the working voltage you are using.
Circuit Diagram of Bridge Rectifier Figure 4
Capacitor : The main basic purpose of electrolytic capacitors is to store electrical energy, which is employed as a filter or smooth ripple output in raw rectified DC. Here we are using capacitor as a filter for power supply.
Electrolyte Capacitor Figure 5
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NV725 Procedure 1. Connect mains cord to the DC Supply at the mains cord socket provided. 2. Switch ON the mains supply. 3. Measure voltage of Fixed Supply using DMM. 4. Slowly increase the voltage of variable supply through Variac knob and find the change in output voltage at the voltmeter provided on the panel. 5. If you connect any DC load to the supply, ammeter will show the current drawn by load.
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NV725 Safety Precautions 1. Before making connections make sure that the AC mains is off and MCB of DC Supply is at off position. 2. Make sure that the earthing of your laboratory is proper and it is connected to the terminal provided back side of DC Supply. 3. Knob of Variac must be at 0 position before switching ON the supply 4. Always connect DC load to the supply.
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NV725 Warranty 1)
We guarantee the product against all manufacturing defects for 24 months from the date of sale by us or through our dealers.
2)
The guarantee does not cover perishable item like cathode ray tubes, crystals, Batteries, Photocells etc.
3)
The guarantee will become void, if a) The product is not operated as per the instructions given in the learning material. b) The agreed payment terms and other conditions of sale a re not followed. c) The customer resells the instrument to another party. d) Any attempt is made to service and modify the instrument.
4)
The non-working of the product is to be communicated to us immediately giving full details of the complaints and defects noticed specifically mentioning the type, serial number of the product and date of purchase etc.
5)
The repair work will be carried out, provided the product is dispatched securely packed and insured. The transportation charges shall be borne by the customer.
List of Accessories 1.
4mm Patch Cord 24” (Red)………………………………….………5 Nos.
2.
4mm Patch Cord 24” (Black)………………………………….…….5 Nos.
3.
Learning Material CD…………………………………….……….…1 No.
4.
Single Phase Mains Cord……………………………..………….......1 No.
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