Test & Measurement Instruments
Insulation Testers, VF Testers & Precision Ohm Meters
A high-voltage diode that measures correctly on a general-purpose multimeter can still fail in service. Forward voltage drop means nothing without a stated forward current; insulation resistance means nothing without a stated test voltage; a milli-ohm reading taken on two-wire leads measures the leads as much as the joint. The instruments that answer those questions properly are built for the measurement — not adapted from a bench meter that happens to have the range.
Ameet Electro Systems (Nashik, Maharashtra) manufactures test and measurement instruments for high-voltage component quality control and electrical maintenance: HV insulation testers, diode VF testers, and precision milli-ohm and micro-ohm meters. Every instrument is designed, assembled, and tested in-house at our facility in Satpur MIDC, Nashik.
These are the same classes of instrument we run on our own production floor. Every AES bridge rectifier assembly is tested at full rated voltage before dispatch, and our 70 kV and 95 kV PCB-type rectifiers carry ETDC vibration-testing certification from an accredited Government of India laboratory. We supply instruments domestically across India and export internationally, despatched FOB Nhava Sheva (JNPT), Navi Mumbai.
Insulation Testers, Meggers & Hipot Testers — Which to Specify
The most common selection question we receive on this range is which instrument actually answers the question the buyer is asking. Three instrument types are routinely confused, and specifying the wrong one produces a number that looks valid and means nothing.
Insulation Resistance Testers
An insulation resistance tester applies a known DC test voltage across an insulation barrier and measures the resulting leakage current, reporting the result as a resistance — typically in megohms or gigohms. The test is non-destructive: the applied voltage is chosen to stress the insulation realistically without breaking it down.
When to specify an insulation resistance tester:
- Routine condition monitoring of motor and transformer windings, cables, and switchgear, where the trend in resistance over time matters more than any single reading
- Incoming-inspection and pre-dispatch checks on high-voltage assemblies
- Verification of insulation after a repair, rewind, or installation, before energising
"Megger" is a brand name that has become a generic term for this instrument — a Megger is an insulation resistance tester, in the same way a Xerox is a photocopier. If a specification calls for a megger, an insulation resistance tester at the correct test voltage meets it.
Hipot / Dielectric Strength Testers
A hipot tester applies a much higher voltage than the insulation will ever see in service, to prove the barrier does not break down. It answers pass/fail, not "how good." It is a proof test, and it is potentially destructive — it is not appropriate for routine trend monitoring.
When to specify a hipot tester: type testing and safety qualification, not periodic maintenance. AES does not manufacture hipot testers; if a hipot test set is what your standard requires, we will say so rather than sell you the wrong instrument.
The Selection Rule
An insulation resistance tester tells you how healthy the insulation is and can be repeated indefinitely. A hipot tester tells you whether it survives a defined overvoltage, once. Specify the first for maintenance and QC; the second for type approval.
If you are unsure which instrument suits your application, contact us with the equipment under test, its rated voltage, and the standard you are testing to. We will advise without obligation — including where the answer is an instrument we do not make.
Product Range
1 — HV Insulation Tester
High-voltage insulation resistance · Bench instrument · Mains-powered
The AES HV insulation tester applies a high-voltage DC test potential across an insulation barrier and reports the resulting insulation resistance. It is built for high-voltage work — transformer and motor windings, cable runs, switchgear, and high-voltage component assemblies — where the low test voltages available on a general-purpose multimeter cannot meaningfully stress the insulation.
We designed the instrument originally around our own requirement: proving the insulation of high-voltage rectifier and diode assemblies before they leave the building. It is supplied to external buyers in the same configuration.
How this instrument is specified. An insulation tester is only useful at the test voltage your standard or work instruction actually calls for, and the resistance range that follows from it. Tell us:
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The equipment under test and its rated voltage
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The DC test voltage your standard or work instruction requires
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The insulation resistance range you need to read across
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The mains supply voltage at your bench, and the destination country
Datasheet: Available on request — contact us with your application and required test voltage and we will send the current specification.
Primary applications: Transformer and motor winding insulation checks; HV cable and switchgear testing; pre-dispatch QC on high-voltage assemblies; HV test laboratory bench use.
2 — Diode VF Tester
Forward voltage drop at defined test current · Production QC · Bench instrument
The AES diode VF tester measures the forward voltage drop (VF) of a diode at a defined forward current. That last clause is the whole point of the instrument: a VF figure quoted without its test current is not a specification, and the diode-check function on a general-purpose multimeter typically sources well under a milliamp — nowhere near the current at which a power or high-voltage diode's real forward characteristic appears.
For a manufacturer building rectifier stacks, VF is also a matching parameter. Diodes placed in a series string should share the reverse voltage predictably, and a device with an outlying forward characteristic is the one that fails first. Measuring VF at a realistic current is how outliers are found before they are assembled into a stack.
This is the test we run on our own HV diode discs and strips. The instrument is available to external buyers building or servicing rectifier assemblies.
How this instrument is specified. The test current is half the measurement, so the instrument is configured to the devices you actually test. Tell us:
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The device type — HV diode disc, diode strip, bridge assembly, or discrete power diode
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The forward current you need to test at
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The VF range you expect to read across, at that current
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The mains supply voltage at your bench, and the destination country
For reference, our own HV components sit at the high end of that range: the ARE20A diode disc is specified at 31 V VF maximum at 1.4 A, and the 1BR70P bridge assembly at 190 V per diode at 1.5 A — figures a general-purpose meter cannot produce.
Datasheet: Available on request — send us the four points above and we will return the current specification and the recommended configuration within one working day.
Primary applications: Incoming and in-process QC in rectifier and diode manufacturing; matching diodes for series stacks; service and repair of HV rectifier assemblies; test-bench use in HV component laboratories.
3 — DMOM-53A — Precision Milli-Ohm Meter
Two ranges · 4-terminal Kelvin · 1 A test current
The DMOM-53A measures low resistance using a four-terminal Kelvin connection, which drives a known current through the sample on one pair of leads and measures the voltage developed across it on a second pair. Because no measurement current flows in the sensing leads, lead and contact resistance drop out of the result — the reason a two-wire meter cannot give a trustworthy reading in the milliohm region.
Two ranges cover the common cases: 20 mΩ at 10 µΩ resolution with a 1 A test current for joints, bonds, contacts, and busbar connections; and 20 Ω at 10 mΩ resolution for windings and low-value resistors. The instrument is housed in a powder-coated metal case and supplied with 4-wire Kelvin clip leads.
Primary applications: Busbar and bolted-joint resistance checks; contact and relay resistance; motor and transformer winding resistance; cable and bond continuity; incoming inspection of low-value resistors.
4 — Precision Micro-Ohm Meter
Eight ranges · 4-terminal Kelvin · Zero adjust
The precision micro-ohm meter extends the same four-terminal Kelvin measurement down into the microhm region and out to 20 kΩ, across eight switchable ranges. Where the DMOM-53A covers the two ranges most maintenance work needs, this instrument suits a laboratory or QC bench that has to measure across the full span — from a weld or crimp at a few hundred microhms up to a winding or precision resistor at kilohms — without changing instruments.
A potentiometer zero adjust allows residual offset to be nulled before a low-range measurement, which is what makes readings at the 2000 µΩ range repeatable. It shares the DMOM-53A's case, display, power supply, and Kelvin lead set.
Primary applications: Laboratory and QC-bench low-resistance measurement; weld, crimp, and braid resistance; shunt and precision-resistor verification; multi-range work where one instrument must cover microhms to kilohms.
Instruments Built by a Component Manufacturer
Most test-equipment suppliers sell instruments. We build high-voltage components and the instruments that qualify them, and the two activities inform each other.
Every AES bridge rectifier assembly is tested at full rated voltage before dispatch; diode discs and strips are tested to datasheet specification before packaging. The insulation tester and the VF tester on this page exist because that QC process needed them. They were specified by the people who had to use them every day on a production floor, then made available to buyers doing the same work.
Three practical consequences for a buyer:
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The test conditions are the ones that matter in production — forward voltage at a realistic forward current, insulation resistance at a test voltage that actually stresses HV insulation, low resistance on a four-terminal connection. Not the conditions that make a specification sheet look good.
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We can talk about the device under test, not just the instrument. If you are testing HV diode assemblies, we make those too, and we can advise on what a normal result looks like.
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Repair and support come from the manufacturer. The instruments are built in Nashik by the same team; there is no import channel between you and the people who designed them.
Standards and Quality
Measurement method: The milli-ohm and micro-ohm meters use four-terminal Kelvin measurement, the standard method for low-resistance measurement where lead and contact resistance would otherwise dominate the result.
In-house testing: All instruments are tested before dispatch.
Manufacturing base: All instruments are designed, assembled, and tested in-house at Satpur MIDC, Nashik — Maharashtra's established industrial corridor. We have been manufacturing electronic assemblies and instruments in-house since 2008.
MSME / Registration: Ameet Electro Systems is MSME UDYAM registered (UDYAM-MH-23-0235305), with export credentials (IEC 3116911487). GSTIN: 27AHZPP6922A1ZY.
Custom Specifications
Our standard instrument range covers the measurements most commonly required in high-voltage component QC and electrical maintenance. For requirements outside the standard range — a different test voltage, an additional measurement range, a specific test current for VF measurement, or an instrument built into an existing test bench — we design to the buyer's brief.
To enquire about a custom specification, provide:
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Instrument type required (insulation tester / VF tester / ohm meter / other)
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The device or equipment under test, and its rating
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Required measurement range, test voltage, or test current
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Supply voltage at the deployment site
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Quantity and required delivery timeline
We will respond with a feasibility assessment within one working day.
Export
We supply test and measurement instruments internationally. Export shipments are packed for sea freight and despatched FOB Nhava Sheva (Jawaharlal Nehru Port, Navi Mumbai). We provide commercial invoice, packing list, and Certificate of Origin (India). Buyers handle import customs in their own country.
Lead time: Confirmed with your quotation. Instrument lead time depends on the configuration and quantity, so we give you a despatch date with the price rather than a range that may not hold — tell us the instrument and quantity and you will have both within one working day.
Supply voltage: The milli-ohm and micro-ohm meters are supplied for 230 V, 50/60 Hz — suitable for India, Australia (240 V), South Africa (230 V), West Africa (220–240 V), and most of Europe and Asia. For 100–120 V markets (North America, Japan), and for the insulation and VF testers in any market, tell us the destination at enquiry stage and we will confirm the supply configuration.
Datasheets: Available on request for all instrument lines. Provide your email or use the contact form below.
Who We Supply
We supply test and measurement instruments to:
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High-voltage component manufacturers running incoming, in-process, and pre-dispatch QC on diodes and rectifier assemblies
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Transformer manufacturers and HV test laboratories performing winding insulation and resistance checks
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Electrical maintenance teams at power utilities, process plants, and industrial facilities
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Switchgear and panel builders verifying bolted-joint and busbar connection resistance
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Technical institutes and calibration laboratories equipping electrical measurement benches
Specific client names are not published without per-client permission; references are available under NDA.
Test and Measurement Instruments
Frequently Asked Questions
What does "wide input range" actually mean on an SMPS?
It is the span of AC input voltage over which the supply holds its rated DC output. A typical industrial module is specified at 85–265 VAC, which covers single-phase mains worldwide. Our PSU-SWR01 is specified at 90–500 VAC, which additionally covers 415 V three-phase line-to-line and industrial supplies well above socket voltage. The practical consequence is that one part number works everywhere, with no input variant to select and no step-down transformer.
Can one SMPS really run on both 230 V and 415 V?
Yes — that is precisely what a 90–500 VAC input range is for. The PSU-SWR01 delivers the same regulated 12 VDC output whether it is fed from a 110 V socket, a 230 V socket, or a 415 V industrial line. This is why equipment builders shipping to multiple territories, and maintenance teams holding spares for mixed installations, specify a wide-input module rather than stocking variants.
What is the difference between an SMPS module and a bench power supply?
An SMPS module is built into equipment, has a fixed output, and is not intended to be adjusted after commissioning. A bench power supply is an instrument with a front panel, adjustable output, and metering, designed to be changed while you work. Specify the module for anything that lives inside a machine; specify the bench supply for development, test, repair, and teaching.
Why does a bench supply need an adjustable current limit?
Setting a current ceiling before applying power means a shorted or mis-wired board draws only the limit you set, instead of everything the supply can deliver. It is the difference between a prototype that survives its first power-up and one that does not. Our 0–30 V / 0–1 A supply has adjustable current from 0 to 1 A for this reason.
Why is a ±15 V supply fixed rather than variable?
±15 V is the standard symmetrical rail pair for analogue circuitry — op-amps, instrumentation amplifiers, and signal conditioning — and those circuits want exactly that voltage. Making it fixed removes the possibility of setting it wrong, which is an advantage on a teaching bench or a production test station running the same assembly repeatedly.
Are AES power supplies tested before dispatch?
Yes. Every unit is tested in-house before it ships, and all power supplies are manufactured under strict quality control at our Nashik facility. If your process requires a specific test regime or a test report with the shipment, raise it with your enquiry and we will confirm in writing what we can supply before you order.
What is the typical lead time and shipping term for power supply orders?
Lead time is confirmed with your quotation — it depends on the product, its configuration, and the quantity, so we give you a despatch date alongside the price rather than a range that may not hold. Export shipments are despatched FOB Nhava Sheva (JNPT, Navi Mumbai), and we provide commercial invoice, packing list, and Certificate of Origin (India). For volume orders, contact us to discuss scheduling.
Can AES build a power supply to a specific output specification?
Yes. Share the required output voltage and current, the incoming supply at the installation site, the physical format, and any compliance marking your market requires. We will respond with a feasibility assessment within one working day.
Request a Board Specification
Request Datasheet or Specification
Provide:
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Instrument of interest (insulation tester / diode VF tester / milli-ohm meter / micro-ohm meter)
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The device or equipment you need to test, and its rating
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Required measurement range, test voltage, or test current
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Quantity required
Email: ameetsys@yahoo.com
We respond within one working day.
Address: Ameet Electro Systems Plot No. 27, Survey No. 76/2A+B, Someshwar Colony Satpur MIDC, Nashik – 422007, Maharashtra, India GSTIN: 27AHZPP6922A1ZY
