Varistor Selection Surge Rating: Walsin’s MOV Export Carries 0 of 6 Fields You Need

A varistor selection surge rating decision needs six fields a datasheet carries and a parametric export usually does not — and we counted zero of the six in Walsin’s own 379-part MOV file. We opened every column ourselves. Working voltage, nominal voltage, tolerance and a bare peak-current number transfer cleanly; clamping voltage, energy and the surge waveform do not exist in this file at all.

---

Venatech Limited, an authorised Walsin distributor in Hong Kong, holds Walsin Technology (Walsin)’s MOV parametric export — Walsin_MOV_ALL.xlsx and Walsin_MOV_FRESH.xlsx, both 379 rows, both identical once compared cell by cell. We hold no MOV datasheet of any kind — not one of our 28 Walsin datasheet PDFs covers a varistor family, and the datasheet folder we checked for this line returns nothing. Every figure below is counted from the export itself, and we say so before a single number follows.

What does Walsin’s MOV parametric export actually contain?

Ten columns and 379 rows, no duplicate part numbers. We opened both export files and confirmed they are byte-for-byte identical in every cell: Part Number, Series, Size, Max Working Volt., Varistor Voltage, Tolerance, Peak Current, Packing, SPQ and MOQ.

Column	Populated rows	What it tells a buyer
Part Number	379 of 379	Identifier only
Series	379 of 379	Standard, High Energy, Super High Energy or Industrial
Size	379 of 379	Disc footprint, 5 mm to 53 mm
Max Working Volt.	379 of 379	Continuous AC rating
Varistor Voltage	379 of 379	Nominal DC voltage at a reference current, not under surge
Tolerance	379 of 379	Always ±10%
Peak Current	379 of 379	A single amp figure, no test condition stated
Packing	0 of 379	Empty
SPQ	0 of 379	Empty
MOQ	0 of 379	Empty

We checked all 379 rows in both files. Three of the ten columns — Packing, SPQ and MOQ — are named but filled on exactly zero rows. That is 30% of the schema contributing nothing, before a single specification question is even asked.

Which columns in the export are empty on every single row?

Packing, SPQ and MOQ, with zero filled cells each, across all 379 part numbers in both export files. We have not seen this counted anywhere. A buyer pulling this file expecting reel size, standard pack quantity or minimum order quantity gets three named columns and no data in any of them — the schema promises packaging information the export does not deliver, and the gap is total, not partial.

That is a commercial gap, not a technical one, and it is the easiest of the two to close: ask Venatech for the current packing specification against the exact part number, and it comes back from a live quote rather than a stale export cell.

What six fields does a surge rating decision need, and how many does the export name?

Zero of six. A surge-rating decision needs, at minimum: clamping (limiting) voltage at a stated test current, an energy rating in joules, the peak current test waveform duration, a derating curve against ambient temperature, an operating temperature range, and an expected lifetime or surge-count rating. We went through all ten columns in Walsin_MOV_ALL.xlsx field by field, and none of the ten names any of the six.

Field a surge decision needs	In the 10-column export?	What the export gives instead
Clamping / limiting voltage at a stated test current	No	Varistor Voltage — a nominal reference figure, not a clamp under surge
Energy rating in joules	No	Nothing. Peak Current is amps, not joules
Peak current test waveform (for example 8/20 µs)	No	A bare amp figure with no duration stated
Derating curve vs ambient temperature	No	Nothing
Operating temperature range	No	Nothing
Expected lifetime / surge-count rating	No	Nothing

Zero of six, across all 10 columns and all 379 rows. The fields that do transfer — footprint, nominal voltage, tolerance, a peak-current number — are the fields a catalogue needs to list a part, not the fields a circuit needs to survive a surge. Confirm every one of the six against Walsin’s own datasheet, which Venatech does not hold for this line, before you freeze a design on a varistor.

Take a stated requirement — 130 Vac working voltage, a confirmed clamping voltage and an 8/20 µs peak-current rating — and run it against four real candidates at that exact voltage point:

Part number	Series	Footprint	Peak current (export)	Match / mismatch vs the stated requirement
SR201K10D	Standard (D)	10 mm	2,500 A	Match on footprint and nominal voltage; mismatch — no clamping voltage or waveform published
SR201K10E	Super High Energy (V)	10 mm	4,000 A	Match on footprint and nominal voltage, higher current number; mismatch — same missing clamping voltage and waveform
SR201K32D	Industrial	32 mm	30,000 A	Match on nominal voltage only; mismatch — larger footprint, and the same two fields absent
SR201K53D	Industrial	53 mm	70,000 A	Match on nominal voltage only; mismatch — largest footprint, highest current number, still no clamping voltage or waveform

All four pass the footprint-or-voltage screen the export supports. None of the four can be confirmed against the stated requirement, because the clamping voltage and the 8/20 µs waveform figure the requirement actually turns on are not in Walsin_MOV_ALL.xlsx for any of the 379 rows — not for these four, and not for any other part in the file.

Does the Peak Current column tell you the test waveform it was measured on?

No. We checked every one of the 21 distinct Peak Current values in the file — from 100 A up to 80,000 A — and found no waveform notation anywhere: no 8/20 µs, no 10/1000 µs, no duration figure of any kind, in any cell, in either export file. A peak current rating on a varistor is only meaningful alongside the pulse waveform it was tested on, because the same disc survives a far higher current on a short 8/20 µs lightning-style pulse than on a longer, more energetic pulse — and this export states the number with no context for which pulse it is.

Why does the word Energy appear in the data if no energy rating is published?

Because it names two series, not a rating. “High Energy” and “Super High Energy” are Walsin’s own series labels in the Series column — 48 parts and 60 parts respectively — and that is the only place the word “Energy” appears anywhere in the file. We searched all 379 rows across all 10 columns for the word, and it surfaces exactly twice, both as series names, never once attached to a joule figure. A buyer reading “High Energy” as a stated energy rating in joules is reading a marketing name, not a specification.

Where do you get clamping voltage, joules and derating if not from this file?

From Walsin’s own series datasheet, which Venatech does not hold today for any MOV series. We hold 28 Walsin datasheets covering 451 pages, and not one of them is a varistor sheet — the same gap we disclose on inductors, disc capacitors, RF and thin film. The honest path is to ask: a specific part-number request is what puts the varistor datasheet on our list to Walsin, rather than Venatech guessing at a mechanism it cannot see.

1. Cross your incumbent varistor on the fields that do transfer — footprint, nominal voltage, tolerance and the bare peak-current number — using the free cross-reference tool. It decodes 18 manufacturers’ part numbers and matches against 800,000+ crossable Walsin part numbers.
2. Check ready stock for which varistor part numbers are physically in Hong Kong today, a dated snapshot as at 23 September 2026.
3. Ask us for the datasheet on your exact part number. We will tell you honestly when Walsin returns it, rather than filling the gap with an export value dressed up as a specification.

Confirm against Walsin’s own datasheet and qualify any crossed part in your own circuit — that step stays with you.

For the full series comparison on the fields that do exist, see MOV varistor series selection: D, E, V and Industrial. For how the footprint-and-voltage grid itself has gaps, see How to choose an MOV varistor. The full range is on the Walsin MOV products page.

The short version

Walsin’s MOV export has 10 columns, 3 of them empty on all 379 rows, and names 0 of the 6 fields a varistor selection surge rating decision actually needs. Clamping voltage, energy in joules, the peak current waveform, derating, operating temperature range and expected lifetime do not appear anywhere in the file. What does transfer — footprint, nominal voltage, tolerance, a bare current number — gets a part onto a shortlist. It does not tell you whether that part survives your surge.

Send us the surge current and waveform your design must absorb, and we will tell you plainly whether the answer lives in Walsin’s parametric export or has to come from a datasheet we do not yet hold — rather than quoting you a figure the export cannot support.

---

Frequently asked questions

<!– wp:rank-math/faq-block {"questions":[{"id":"faq-question-01","title":"Does Walsin's varistor export include a clamping voltage figure?","content":"No. The export states Varistor Voltage, a nominal reference figure measured at a stated reference current, not a clamping or limiting voltage under a surge pulse. We checked all 10 columns across all 379 rows and found no clamping-voltage field anywhere in the file.”,”visible”:true},{“id”:”faq-question-02″,”title”:”Is there an energy rating in joules anywhere in Walsin’s MOV data?”,”content”:”No. The word \”Energy\” appears exactly twice in the 379-row export, both times as part of a series name — \”High Energy\” and \”Super High Energy\” — never as a joule figure. The only current-related column is Peak Current, stated in amps with no energy or waveform context.”,”visible”:true},{“id”:”faq-question-03″,”title”:”What test waveform is Walsin’s varistor Peak Current rating measured on?”,”content”:”The export does not say. We checked every one of the 21 distinct Peak Current values, from 100 A to 80,000 A, and found no waveform notation — no 8/20 microsecond or 10/1000 microsecond marking — on any row in either export file. Confirm the test condition with Walsin before using the figure in a surge calculation.”,”visible”:true},{“id”:”faq-question-04″,”title”:”Which three columns in Walsin’s MOV export are always empty?”,”content”:”Packing, SPQ and MOQ. We checked all 379 rows in both Walsin_MOV_ALL.xlsx and Walsin_MOV_FRESH.xlsx and found zero filled cells in any of the three, across every part number in the file.”,”visible”:true},{“id”:”faq-question-05″,”title”:”Does Venatech hold a Walsin varistor datasheet?”,”content”:”No. Venatech holds 28 Walsin datasheets totalling 451 pages, and none of them covers a varistor family. Every MOV figure we publish comes from the parametric export, and the series datasheet is on our request list to Walsin rather than something we can paraphrase today.”,”visible”:true},{“id”:”faq-question-06″,”title”:”What does Walsin’s MOV export tell you reliably?”,”content”:”Footprint, from 5 mm to 53 mm, nominal working and varistor voltage, a single plus-or-minus-10% tolerance figure, and a bare peak current number. All four are populated on all 379 rows and transfer cleanly into a first-pass cross reference. None of the four is sufficient on its own to confirm a surge rating.”,”visible”:true}],”listStyle”:””,”titleWrapper”:”h3″,”titleCssClasses”:””,”contentCssClasses”:””,”sizeSlug”:””} –>

---