Lineman's Reference - XFMR LAB
Description
Learn it. Wire it. Energize it. Built by a working journeyman lineman for linemen and their apprentices. The XFMR Lab simulates distribution transformer banks driven by your own wiring — the metering, fusing, and faulting all behave the way you'd expect in the field. NEW IN 2.0 — BUILT-IN TRANSFORMER TRAINING (Replacing XFMR INFO) Six guided lessons take you from "what's a transformer?" to wiring a 3-pot bank: • Start Here — What is a Transformer? • Dual H Bushings — The Two Wirings & the Nameplate • The Tap Changer — One Pot, Multiple System Voltages • Three-Phase — The Three Phases and How They're Related • Bank Identification — Delta or Wye, Open or Closed • Your First Bank: Delta-Wye Closed (120/208) • More lessons on the way! Work the lessons in order, or jump straight to the labs. ALSO NEW IN 2.0 • The Sandbox (Beta) — wire anything from scratch in a COMPLETELY-customizable lab, with live, vector-based voltage and fault logic baked in. • Death Traps — scenario-based transformer traps linemen run into — and how to navigate them safely. • A brand-new look across every lab — new graphics, sharper, faster, & easier to read in the field. • Voltmeter you can now drag with two fingers; readings update as the leads move. • Parallel the secondary coils by hand in wye secondary labs • Stats that track lab completions, quiz scoring and for-fun stuff like the number of fuses you've blown. • User Customizations - the user can now alter the spec of their labs; from grounding to parallel coil cutover-direction, requiring the 4th cutout, tap changer implementation and more. • 2.0 is FREE for everyone who already owns XFMR Lab — thank you for years of feedback and encouragement. WHAT YOU GET Single Phase — Single Bushing · Dual Bushing Three Phase (closed) — Delta-Delta · Delta-Wye · Wye-Delta · Wye-Wye Three Phase (open) — Open Delta-Delta · Open Wye-Delta Misc — Paralleling · 4th Cutout · Death Traps (6 Scenarios) Advanced — Straight 480 · 240/480 · 277/480 · Corner-Grounded 240/480 · Wye-Wye 5-Wire (120/240 + 120/208) - all now able to be wired up Wye AND Delta on the topside The Sandbox (Beta) EVERY FUTURE UPDATE IS FREE - THE APP IS A ONE-TIME PURCHASE. I'm always working on new updates. TOOLS & REFERENCE • Volt, ohm and rotation meters with real behavior • Nameplate, secondary coil and tap changer animations • Reference diagrams for every standard bank Learning Mode walks apprentices through every wrong-connection check. Journeymen and experienced users can keep this turned off if they'd like. QUIZZES • Classic Quiz — Select each lab you want in your quiz - with graded scoring across each lab. • Advanced Quiz — You're provided with the job-site info and need to pick the right nameplate and coil setup, then wire it. • Bank ID - A beginner's quiz tied into the new XFMR Training lesson plan. The user is provided with different primary and secondary wirings and must correctly identify them. Used by 30,000+ linemen since 2021. Questions? Suggestions? Reach me at info@digitalapprentice.net
What's New
XFMR Lab 2.0 — the biggest update since launch. NEW: Built-in Transformer Training (replaces XFMR Info). Six guided lessons take you from "what's a transformer?" to wiring a 3-pot bank — Start Here, Dual H Bushings, The Tap Changer, Three-Phase, Bank Identification, and Your First Bank: Delta-Wye Closed. More lessons on the way. More lessons on the way soon! NEW: The Sandbox (Beta) — wire anything from scratch in a fully customizable lab, with live, vector-based voltage and fault logic baked in. NEW: Death Traps — scenario-based transformer traps linemen run into, and how to navigate them safely (3 scenarios with more on the way). NEW: User Customizations — set the spec of your own labs: grounding, parallel coil cutover direction, requiring the 4th cutout, tap changers, and more. NEW: Bank ID quiz — a beginner quiz tied to the Training lessons; identify primary and secondary wirings on sight. NEW: Stats — track lab completions, quiz scores, and for-fun numbers like how many fuses you've blown. ALSO: • A brand-new look across every lab — new graphics, sharper and easier to read in the field. • Tap changer, nameplate, and secondary coil animations. • Parallel the secondary coils by hand in wye-secondary labs. • Advanced labs can now be wired Wye OR Delta on the topside. • Voltmeter now drags with two fingers; readings update as the leads move. 2.0 is FREE for everyone who already owns XFMR Lab — and every future update is free, too. One-time purchase. Thank you for years of feedback and encouragement.
Details
- Developer
- Digital Apprentice LLC
- Main Category
- Education
- Version
- 2.0.3
- Version Release
- 2026-07-04
- Initial Release
- 2021-09-12
- Size
- 65 MB
- Age Rating
- 4+
- Price
- USD 19.99
- Languages
- EN
- Bundle ID
- digitalapprentice.xfmr
- Version Rating
- ★ 4.31 (162)
- First Seen
- 2026-05-28
Metadata updated 2026-07-19
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Competitive Benchmark — Education Top 10
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User Reviews
App is far to clunky, not worth using when you can only wire up 1/3 of the banks due to the lines not connecting.
Learning a lot from this app. Only problem I’ve come across is how to tie the H1/H2 bushings to the tank ground and neutral
Your eye delta is wrong. Other than that good app.
Great app just noticed that on some of the banks you can’t bus the secondary x2 to x2 bushing for delta secondary’s. It use to work but if the developers can fix that then it would get that 5th star in my book
The app has some flaws but nothing you can’t work around. Helped me a lot on learning transformer configurations.
I really like this app, I recommend it to my apprentices to learn the concept of banking transformers. What I do no like is that I can’t select to build banks with subtractive transformers. Not every system is less than 8kv. Also, when building a bank, if the wiring on the X bushings is not to the exact phase it’s drawn on the diagrams, it won’t accept the answer.
This is a great app, let me just start with that. It would be great if you could build your own banks and check voltage and what not. The set diagrams are awesome but being able to play around with different connections would make it better. Also tap changer settings and info would also be a great addition.
If you thought you’d be able to run a lot of different scenarios with this don’t bother. The app won’t let you do a ton of stuff and if you’re trying to use it to show an apprentice or something their mistake and recreate it digitally it almost certainly won’t accurately recreate that. Basically you build it correct or it doesn’t much do anything, not much point of this unless you really just want an interactive diagram because you can’t follow one that doesn’t have movable parts—which makes zero sense to me.
Awesome app helped me get my secondary connections down but it would be even better you guys added a create your own bank option just so guys can get a better grasp. Also be helpful if you could add a wye bank that stays in series. Hope to see more options in the future.
How do you connect the h2 to the neutral everytime I tie them in I can get them to turn white but they come in upside down. How do I make them look like the picture ? I’m sure there is a way to do it but I’ve been messing with this app a few days and have yet to figure it out
Reviews are collected only for apps with detected changes (new entries or sharp risers).