Build a d.c. motor: what makes it turn faster sim
Build a school motor kit by dragging the parts (wind the coil, press the brushes onto the split ring, plug the leads into the supply, set the rheostat), switch on, count its turns with a light gate on a paper flag, and test one factor at a time (current, turns, a second pair of magnets, a soft-iron core) in your own table and graph; see why the turning effect is biggest when the coil is level, swap in slip rings, and reverse the current, the field or both.
Electromagnetism: the d.c. motor · covers the O-Level, IGCSE, GCSE topic
What the sim shows
Model. Force on each side N B I L at right angles to the field and the current, worked in the frame the student sees (Fleming's left-hand rule); turning effect N B I A cos(angle from level). Coil 40 mm by 30 mm; field 0.04 T (one pair) or 0.065 T (two pairs), × 1.6 with the soft-iron cylinder (all chosen). Split ring: the coil's current reverses as it passes upright; slip rings: it never reverses. Motion stepped every 0.25 ms with a steady friction and a drag (chosen); no back e.m.f. (beyond the syllabus). The current: the shared circuit model, 6.0 V supply, rheostat 0 to 25 Ω; the page refuses more than 2.0 A. Nothing runs on its own: the coil turns after you switch on, and the counter counts only when you start it, for the time you chose.
- The coil (it turns on the axle)
- Motor kit, magnets on a steel yoke, light gate and counter, supply, ammeter, rheostat, reel of wire, spare parts
Use it in your lessons
- Try it here: anyone can unlock 2 figures free, and a free account unlocks up to 5. Runs on a laptop, a Chromebook or a phone; nothing to install.
- Present it and share student links with the teacher plan, from US$5 a month, billed yearly.
- Put it on your own website or LMS for US$9, paid once, or every sim from US$29 a month.
Free guide: 12 practicals as sims, and how to run one in a lesson →
Need a version for your exact set-up? Have one made: US$49 a figure in an order of 5.
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