Quick answer. Every item here is specified by resistance and power rating together, with the condition the rating assumes, and the listing gives neither figure. EC-0001 to EC-0008 are power resistors and variable transformers - for load banks, motor braking, current measurement and voltage control - not small signal parts. So work out the power your circuit will actually dissipate, specify a resistor comfortably above it, and state whether the rating is for free air or heatsink mounting, and at what ambient temperature. An aluminium housed resistor (EC-0004) rated on a heatsink will not survive its catalogue figure if it is run unmounted.
Despite the general name, this listing is specifically power resistors and variable transformers: eight items in the EC series, EC-0001 to EC-0008, covering wire wound resistors in four constructions, a dynamic braking resistor, loading rheostats, shunts and auto variable transformers. These are the components used for load banks, motor braking, current measurement and voltage control, not the small signal components a breadboard needs. Every one of them is specified by resistance and power rating together, and the listing gives neither.
| Code | Construction | Where it fits |
|---|---|---|
| EC-0001 | Wire wound | The base construction for all of these: resistance wire wound on a former. Handles far more power than a film resistor and holds its value, at the cost of some inductance, which matters at high frequency and does not at mains frequency. |
| EC-0002 | Axial type | Leaded, for mounting on a board or in free air. The convenient form for modest powers. |
| EC-0003 | Ceramic encased | The element is sealed in a ceramic body, which protects it and raises the surface temperature it will tolerate. The usual choice where the resistor is exposed or handled. |
| EC-0004 | Aluminium housed | Built to be bolted to a heatsink or a metal chassis, which carries the heat away and lets a small body dissipate much more power. The rating normally assumes it is mounted on a heatsink, so ask what the free-air rating is as well, because an aluminium housed resistor run unmounted will not survive its catalogue figure. |
A power resistor is quoted as a resistance in ohms at a wattage, and neither figure means anything alone. Work out the power your circuit will actually dissipate, then specify a resistor comfortably above it: continuous duty near the rated figure runs hot, so headroom is the normal practice rather than a luxury. On any enquiry in this range, give or ask for:
| Item | Code | What it does, and what to specify |
|---|---|---|
| Dynamic braking resistor | EC-0005 | Absorbs the energy a motor returns when it is decelerated, turning it into heat instead of letting it push the drive's DC link voltage up. Specify the resistance the drive requires, the peak power, the duty cycle and the energy per braking event, because this part is sized on energy rather than on continuous power. Ask also about the enclosure and whether a thermal switch is fitted, since a braking resistor that fails hot is a fire risk. |
| Loading rheostats | EC-0006 | An adjustable resistance used as a variable load, for machine testing and for loading a supply or generator in a laboratory. Specify the resistance range, the current rating at each setting rather than only at maximum, the number of steps or whether adjustment is continuous, and the cooling arrangement. Ask whether the terminals are shrouded, because a loading rheostat sits at full supply voltage in a student laboratory. |
| Shunts | EC-0007 | A precision low resistance placed in a circuit so current can be measured as the small voltage across it. Specify the current rating and the full-scale millivolt output, which is the pair that matches a shunt to a meter, plus the accuracy class and the temperature coefficient. A shunt is a measuring instrument, so ask whether a calibration certificate is available. |
| Auto variable transformers | EC-0008 | A continuously variable AC output taken from a single tapped winding by a moving brush. Specify the input voltage, the output voltage range, the current or kVA rating, and whether it is single or three phase, open or enclosed, and panel or bench mounted. Ask explicitly whether the output is isolated from the input: in an autotransformer it normally is not, so the output shares a connection with the supply. That matters for safety in a teaching laboratory, and where isolation is needed an isolation transformer has to be added in front of it. |
Three practical points on buying these for student use. First, everything here converts electrical energy into heat, so ask for the surface temperature at rated load and plan the mounting and ventilation around it; a resistor that works correctly can still burn a hand. Second, ask about terminal shrouding and guards for anything students touch while energised. Third, ask for the applicable safety standard by number, and confirm the supply voltage and frequency for your country on the variable transformers. Any performance figure quoted is confirmed in writing on the quotation; ask for its basis.
This listing does not cover the resistors, capacitors, diodes and ICs that stock a breadboard. Trainer kits supplied with component sets are under Digital Analog Trainers and Kits and Basic Electronics Trainers, which includes a project board trainer. Device testing is under IC Tester and Digital IC Tester. Ask the sales team directly for a component stock list, since it is not published here.
Rheostats also appear in the school range under Lab Equipments. Motor and machine work is under Electrical Engineering Trainers and Power Electronics Trainers, measurement under Testing and Measuring Lab Trainers, and instrumentation under Instrumentation Trainers. Parent range: Electronics Lab Trainer Kits.
Give the resistance and the power rating together, with the mounting condition the rating assumes, and the duty. For a shunt give the current and the millivolt output; for a variable transformer give the current or kVA and the phase. For example a ceramic encased wire wound resistor (EC-0003) at a stated ohms and watts in free air, or an auto variable transformer (EC-0008) at a stated kVA, single phase, enclosed. Contact Ray Export for prices, data sheets and lead times.
Choose by how the resistor is mounted and how much heat it must shed. EC-0001 is the base wire wound construction, which handles far more power than a film resistor and holds its value, with some inductance that matters at high frequency but not at mains frequency. The axial type (EC-0002) is leaded, for a board or free air at modest powers. The ceramic encased type (EC-0003) is the usual choice where the resistor is exposed or handled. The aluminium housed type (EC-0004) is built to bolt to a heatsink, so ask its free-air rating too.
Give the resistance and the power rating together, because neither means anything alone, and specify comfortably above the power your circuit will dissipate. Add the tolerance as a percentage; the condition the power rating assumes, free air or heatsink mounted and at what ambient temperature; the temperature coefficient if the value must hold as the part warms; the maximum working voltage; the mounting, terminations and dimensions; and the duty, continuous or intermittent with stated on and off times.
On energy rather than continuous power. The dynamic braking resistor (EC-0005) absorbs the energy a motor returns when it is decelerated, turning it into heat instead of letting it push the drive's DC link voltage up. Specify the resistance the drive requires, the peak power, the duty cycle and the energy per braking event. Ask also about the enclosure and whether a thermal switch is fitted, since a braking resistor that fails hot is a fire risk, and plan its mounting and ventilation around the heat it sheds.
A loading rheostat (EC-0006) is an adjustable resistance used as a variable load, for machine testing and for loading a supply or generator in a laboratory. Specify the resistance range, the current rating at each setting rather than only at maximum, the number of steps or whether adjustment is continuous, and the cooling arrangement. Ask whether the terminals are shrouded, because a loading rheostat sits at full supply voltage in a student laboratory, and ask its surface temperature at rated load so the bench can be planned around it.
By two figures together: the current rating and the full-scale millivolt output. A shunt (EC-0007) is a precision low resistance placed in a circuit so current can be measured as the small voltage across it, so its millivolt output at full current must match the meter's range. Specify the accuracy class and the temperature coefficient as well, since holding its value as it warms is the whole point of a shunt. Because a shunt is a measuring instrument, ask whether a calibration certificate can be supplied with it.
Normally not. An auto variable transformer (EC-0008) takes a continuously variable output from a single tapped winding by a moving brush, so the output shares a connection with the supply. That matters for safety in a teaching laboratory, and where isolation is needed an isolation transformer has to be added in front of it. Ask explicitly about isolation, and specify the input voltage, the output voltage range, the current or kVA rating, single or three phase, open or enclosed, and panel or bench mounting.
Ray Export is a manufacturer and exporter of laboratory, scientific and educational equipment based at Plot No. 449, HSIIDC Industrial Area, Saha, Ambala, Haryana 133104, India. Enquiries: [email protected], +91-9817319615.
Written by Palak Mall, Senior Content Writer. Technically reviewed by Arvind Kumar, Lab Equipment Specialist, 12+ years in laboratory and testing instrumentation. Last updated: 17 October 2026.
Specifications, ratings and the conditions behind them are confirmed in writing on the quotation, together with the basis of any performance figure. For certificates, including calibration certificates and the electrical safety standard an item is built to, contact us for the latest copies of the relevant certificates. No price is quoted on this page. Listing notes: the listing name is general but its eight items are power resistors and variable transformers; none of the eight is listed with a resistance or power rating; and no small signal component stock list is published, so ask the sales team for one.
A resistor is a two terminal electronic part that creates a voltage over its terminals that is relative to the electric current going through it as per Ohm's law
Our wire wound resistors show elite life and are by and large broadly utilized as a part of electronic businesses, for example, open address frameworks, UPS, Invertor, Panels and so forth.
Particulars:
· An extensive variety of Resistance accessible in 1w to 10000 w.
· Values from E001 to 500 k.
· Non inductive adaptation accessible.
· Higher wattage resistors for extraordinary applications can be made.
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Resistors twisted on high alumina earthenware poles fitted in steel tops having tin platted copper leads for association.
Highlights:
· Small in estimate
· Wide range from 0.5 w to 20 w.
· Ohmic qualities from E 01 - 10 K Ohms.
· Coated with high temperature fire verification synthetic concoctions.
· Instant over-burden limit.
· For High opposition esteem, the winding center is supplanted by metal oxide film cutting center.
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Resistors twisted on high alumina fired poles, fitted in steel tops having tin platted copper leads/metal clasps for terminations are embodied utilizing heat confirmation substance in fired pontoons/funnels.
Particulars:
· Wide range accessible from 1 w - 40 w.
· Ohmic Values E01 - 100 K.
· Instant Overload capacity.
· Excellent warmth scattering.
· Non-combustible/warm confirmation substance confines self start because of stream of over present, at that point
indicated.
· For high opposition esteem, the winding center is supplanted by metal oxide film cutting center .
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A resistor encased in an aluminum lodging regularly having a level base for mounting. Aluminum encased resistors are twisted with Copper Nickel or Nickel Chromium wire, on a clay center fitted with end tops, to acquire required opposition. The winded get together is then typified in an anodized warm sink utilizing high temperature shaping compound.
Our powerful wire wound resistors display superior life and are widely utilized crosswise over industry. These resistors consent to global quality and wellbeing norms.
Details:
· An extensive variety of Resistance accessible in 5w to 300 w.
· Small measurement and superb warmth exchange.
· Good Electrical Stability, Reliability and Mechanically quality.
· Values from E01 to 100 k.
· Non inductive adaptation accessible.
· Higher wattage resistors for extraordinary applications can be made.
Contact Ray Export for your School, College Civil and Mechanical Engineering Lab Instruments. We are the best engineering educational equipments india, engineering equipments distributors, engineering lab instruments, engineering equipments manufacturer, thermodynamics engineering equipment, engineering educational lab equipments in Ambala, India.
A braking resistor is a high wattage resistors utilized as a part of engine control to help an engine stop rapidly through a procedure known as Dynamic Braking.Our high power wire wound resistors display superior life and are widely utilized crosswise over industry. These resistors go along to universal quality and wellbeing norms.
Details:
· An extensive variety of Resistance accessible in 40w to 10000 w.
· Values from E01 to 100 k.
· Excellent warmth exchange and little measurement.
· Good Electrical Stability, Reliability and Mechanically quality.
· Non inductive rendition accessible.
· Higher wattage resistors for exceptional applications can be made.
Contact Ray Export for your School, College Civil and Mechanical Engineering Lab Instruments. We are the best engineering educational equipments india, engineering equipments distributors, engineering lab instruments, engineering equipments manufacturer, thermodynamics engineering equipment, engineering educational lab equipments in Ambala, India.
Stacking Rheostats are a test hardware, intended to meet the prerequisite of industry and test research centers. Ray Export make Loading Rheostats are being utilized as a part of electrical/electronic ventures and research facilities for stack testing of switches, transformers, generators and different segments. The Loading Rheostats are evaluated for consistent utilize and they meet the pertinent IS determinations and are broadly being used.
Highlights:
· A Number of resistors are gathered in arrangement and/or parallel blend to give the predetermined evaluations. The resistors are twisted with Copper-Nickel/Nickel-Chrome amalgam wire, having low temperature co-proficient. Formers are vitreous enameled MS funnels or non - hygroscopic artistic tubes.
· Heavy obligation rotational switches or MCB's are given to Increase or decline the obstruction in steps.
· Heavy obligation protected writes terminals are given on the front board will likewise having essential circuits and which additionally fill in as info/yield terminals.
· The unit is housed in a very much created desk area with important balances for ventilation, having castors haggles fan.
Details:
Temperature Co-productive Resistance
+/ - half ppm - +/ - 100% ppm
Kind of Resistance Wire
Self oxidized/Bright Wire
Sythesis of Resistance Wire
56/44: copper/nickel or
80/20: nickel chrome
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The Shunts are made in agreement to the necessity of the business in PCB coordinate mountable compose and customary square writes mounting. The resistive material is of best quality Cu/Ni or Ni/Cr composite, manganim wire having low temperature co-proficient. An extensive variety of Shunts are accessible from 20 amp. to 3000 amp., according to the prerequisite in various voltages.
Details:
· Open Frame Axial and PCB Mounting
· Range : 0.001 - 1 ohms
· Power : 0.5 W - 3 W
· Tolerance : +5%, +2%, +1%
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Particulars:
· Rated for 240V A.C. 50/60Hz.
· Single stage supply and three stage show for 415V A.C. 50/60Hz three stage 4 wire supply.
· The yield voltage of these Toroidal or variable transformer can be fluctuated easily more than two
ranges:
· Zero to full supply voltage
· Zero to approx. 12% higher than the supply voltage
· These auto transformers or dimmers are Suitable for indoor use on most extreme surrounding temperature of 45oC.
· Variable Auto Transformers are evaluated 240 volts Input and 0-270Volts yield. So also, three 240-volt units are ganged in a star association with result in a 470-volt line-to-line three-stage gathering. For 480-volt open delta applications, two 240-volt units are utilized as a part of arrangement in every one of the two legs of the open delta get together. In any of the above voltage applications, higher current necessities are met by paralleling at least two units in the ganged get together.
Contact Ray Export for your School, College Civil and Mechanical Engineering Lab Instruments. We are the best engineering educational equipments india, engineering equipments distributors, engineering lab instruments, engineering equipments manufacturer, thermodynamics engineering equipment, engineering educational lab equipments in Ambala, India.
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