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Lineman's Reference - XFMR LAB icon

Lineman's Reference - XFMR LAB

by Digital Apprentice LLC
Pay once $19.99 4.7 · 417 ratingsiPhone & iPad
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About Lineman's Reference - XFMR LAB

Learn it. Wire it. Energize it. Check your work.

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.

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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

How it charges

Pay once $19.99

Paid once — $19.99 — with no in-app purchases.

The store lists no in-app purchases.

Checked against the store listing on Oct 29, 2026. Something wrong? Tell us

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