Transformer core flux density Bm — design check calculator
Type in your winding design data and the engine computes Bm from E_rms = 4.44 x f x N x A_c x Bm. It also works backwards: give a target Bm and it returns the turns or the core section you need. Units are declared on every field and echoed back with the result.
Sample case pre-filled: phase voltage E_rms = 230 V, f = 50 Hz, N = 100 turns, core net section A_c = 65 cm2, giving Bm = 1.594 T. Overwrite every field with your own values - every number below is computed by the engine, not by this page.
RequiredRecommendedLeft bar: blue = required, gold = recommended. Optional and advanced fields are collapsed by default.
Sine wave at power frequency only; square-wave or harmonic excitation is not supported (no coefficient is invented). Bm limit is optional - leave it empty and the page returns Bm only, with no pass/fail.
Fill in every required value before calculating - a missing value is never replaced by a default, and the frequency is never defaulted to 50 Hz.
This is a design-check calculator. It does not replace the manufacturer design and type tests - the final design is governed by the manufacturer data sheet and the type-test report.
Industry-practice reference band, not a standard mandatory value and not a default. It does not enter the pass/fail judgement; always confirm with your own silicon-steel grade datasheet.
Not calculated yet - fill in the design data and press Calculate.
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E_rms = 4.44 x f x N x A_c x Bm is the engineering form of Faraday induction law (4.44 = 2 x pi / sqrt(2)). For an inductor: lambda_max = L x I_peak and Bm = lambda_max / (N x A_c), valid in the linear region only.
Sine wave at power frequency only. Square-wave or harmonic excitation is out of scope and no coefficient is given for it. Saturation (L-I curve) needs the manufacturer curve (IEC 60076-6 gives no default curve; same basis as engines/reactor-transient.js).
Industry-practice reference band (not a standard value): CRGO (cold-rolled grain-oriented) transformer cores are commonly designed around 1.65-1.75 T. Source: GNEE/ChinaSiliconSteel technical note "Most distribution cores are designed between 1.65 T and 1.75 T". IEC 60404-8-7 specifies the grade and its loss at the reference polarizations 1.5 / 1.7 T, not a mandatory working flux density.
This page performs no calculation of its own. Every number and the curve come from the engine module through the standard study endpoint (study=core-flux); the page only maps your input to the request and displays what comes back.
Sample case: E_rms = 230 V, f = 50 Hz, N = 100, A_c = 65 cm2, so Bm = 230 / (4.44 x 50 x 100 x 0.0065) = 1.5939 T.
This is a design check for one magnetic circuit. Core saturation (the L-I curve) and the flux waveform need the manufacturer curve - open the Loss / temperature-rise / core-flux reference for those.