D. Edward Mitchell 16:00, 14 April 2020 (UTC) Hello World! groupKOS Developer Share UNDER CONSTRUCTION
MOT DC Power Supply Project
Imaginarium → Plans
MOT Testing ° Hi-Amp DC Power Supply ° Transductor Project (Vintage Aeronautical) ° Pinch Welder ° Isolation Transformers ° Very High Voltage Flux Capacitor (Caution!)
- 1 Don notes while morphing this page from pipe dream toward production worthiness
- 2 Design vectors
- 3 Really simple DC power-supply circuit schematic
- 4 The power supply outputs connected backward
- 5 MOT Spec-s
- 6 MOT load limits
- 7 The video series: The Evolution of a microwave oven transformer to an IoT telemeterized and remotely controlled precision (ish) DC 30 ampere power supply with configurable settable ranges and thresholds and a cup holder
12:00:00 AM GMT Jan 1, 1900 Developer Msg: Standby for startup. MOT Priority, medium high. MOT Testing and Handling is top on MOT list.
Don notes while morphing this page from pipe dream toward production worthiness
This project is a DIY DC power supply made with a microwave oven transformer (MOT), plus some heavy full-wave diode bridges  . Nuts, bolts, custom connectors (big ones), with tools and TLC make a family heirloom.
But then, some over-kill engineering and a feature set a closet alchemist can appreciate —and what's to keep the best power supply project at 7.8 kilo-foot(s) from being an overwhelming lure to click...
- Stringent ergonomics
- Prudent over-kill safety
- Magnetic-latching power-on switch (power-off interrupted)
- artistic style may be applied
- cleaved selenite for light-pipes to transfer panel indicator lights from an LED to the panel display surface
- grocery-bags re-melted into cabinet foot pads
- Precision laser-pointer-Galvanometer rear-projection-on-translucent-scale (in the box, projecting to a transparent wood inlay)
- Vernier-dials with Moiré patterns Vernier-morphing (like numbers appearing in the pattern per the rotation of a dial)
- Delay-on / delay-off
- Threshold relays and range monitors (from a DIY automation library developing standard home automation components
- —A DIY manual for intelligent people –with pictures
- Water cooling fittings (in/out)
- Stackable case joiner frame, and a joiner-frame on castors for under the stack.
The Alchemist's Options for Power Supplies
- Locking castors
- One handle for lugging around
- Alexa enabled
- Two handles for lifting with a friend
- Works upright or downright
- Air-ducting to re-purpose waste heat as a heated Ottoman
- WiFi MQTT internal telemetry (temperature, volts, amps; average/highest/lowest/present/yadee)
- Smart option w/Android app and software power-control-profiles for charging batteries, electrocuting fishing worms, etc.
- Embedded MQTT server hosting telemetry for any wireless automation in the home (likely on a Raspberry Pi)
Really expensive option
- Vintage industrial high-dollar parallelogram lift system, for when the cabinet-top working surface needs precision vertical alignment.
Really simple DC power-supply circuit schematic
The power supply outputs connected backward
'Backwards' means, put the lines voltage (120 vac) onto the fine-windings of the MOT, normally the secondary high-voltage output windings. When wired backwards, the voltage output is at popular levels for people like us.
MOT backwards output Unrectified: 14 VAC (unloaded) MOT backwards output Rectified: (14 * 1.414) = ~20 VDC (unloaded)
If an MOT is used backward for modest loads (under 20 amps at 12 vdc) the thermal loading of the MOT is negligible (get a second opinion!). But! Ventilation is required to avoid heat build-up. Enclose only in a wafty box, breezy.
MOT load limits
- These backwards ball-park figures need verification with tests. Stay tuned.
A 20-amp circuit breaker, loaded at 80% pulls 16 Amperes AC In wattage that's 120 X 16 = 1920 watts. That's a good target to stay below for a respectable power supply that may pass down for generations.
An MOT DC supply would, roughly estimating, produce 50 Amperes DC against a 1000 Watt load.
Load-limit by the user beneath smoking-threshold is advisable.
My grandmother always said, "Don't draw more wattage from your MOT power supply than the original microwave oven was designed to handle." Plus, air-cooling is required for periods of high-current use that would smoke the coils without cooling. Grandmother hated that.
The video series: The Evolution of a microwave oven transformer to an IoT telemeterized and remotely controlled precision (ish) DC 30 ampere power supply with configurable settable ranges and thresholds and a cup holder
Safely removing a(an) MOT from a microwave oven's insides
Testing the MOT for what it is
Shameless use of the MOT for what it is
An MOT demands caution !
power supply evolution in DIY video series
- Every techno-geek needs a custom power-supply on the web
- Do you know anyone with a power supply that has its own Tweeter account?
- Inspire the design evolution with your comments!
- Enter your comments on the YouTube video.
- Comment directly to Don aght groupKOS doght cφm.
How to talk to a(n) MOT
1) MOT are you there?
- MOT.status.on = true
- Response: True, or nothing if not there.
- Alias of #1
- Response: A JSON or HTML or CSV file is returned containing named values of telemetric data.
4) MOT.set(name, MOTley)
5) MOT.set(datetime, yyyy.mm.dd.hh.mm.ss)
6) MOT.set(output, 4.99v)
- Response: A named-value of the current voltage reading, e.g., "Output: 4.99v".
7) MOT.set(current-limit, 40 amperes)
8) MOT.set(supply-line-breaker-threshold, 16 amperes) (A soft-breaker)
9) MOT.login(username, security-key)
- Response: Status report. See #3.
- Power Supply Design Notes