Lineman's Reference - XFMR LAB
iOS Universel / Education
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.
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
Quoi de neuf dans la dernière version ?
New
• Amp clamp-on meter in the Sandbox: pull it out of the tool drawer, clamp it on any wire, and read the real current on that conductor. Try it on a loaded secondary leg (~100 A) vs. the primary jumper (~1.7 A), or on a 3-phase-loaded delta corner to catch the √3 between winding and line current.
• Fourth-cutout lab rebuilt as a guided, hands-on walkthrough. You energize the bank with the fourth cutout open and watch the ferroresonance blow happen, instead of just reading about it. Finishes with an unaided practice run you grade yourself.
• New customization option for starting Wye labs with the transformers already cut-over to the direction of your choice.
Improved
• If the app is waiting on Tutorial completion, tapping a locked button now tells you why and that it takes about 5 minutes. Longtime users upgrading from 1.x get a Skip Tutorial option after a quick look at what's new in 2.0.
• Learning Mode warning indicators now update live as you wire: the (!) flags appear and clear while you work, not only when you hit Check Work.
• The voltmeter steps out of the way while you drag a lead or draw a wire, then slides back so the reading stays visible.
• The correct-wiring diagram now shows the high leg on the phase you've actually set, instead of cycling through all three.
• Sandbox vector wheel now reads in the standard orientation (A at the 8 o'clock position) with a phase-displacement readout.
• Sharper splash screen update
Fixed
• Wire delete now works along the full length of every wire, including the ones that used to have dead spots, and no longer fires in the empty corner of an L-shaped run.
• Corner-ground and several banking labs no longer blow a fuse on some correct wirings.
• Voltages across the bank read true after a fuse blows, and a pot with its coils cut to series now reads the correct 240/120/120 split on wye labs.
• Banking nameplate always shows the correct primary voltage.
• Numerous other small bug fixes across each lab
(Existing users: thank you for the reports and feedback!)
