Small wind / Buyer questions
Application integration
Can a heater's ten-minute average power hide a much larger repeated input demand?
The short answer
Yes. A heater controller can alternate full-power intervals with non-firing intervals, producing a moderate long-window average while repeatedly drawing much higher input when on. The supply must support the actual waveform and timing. A ten-minute average useful for energy accounting is not automatically an adequate continuous rating for a source or switching device.
Identify the actual control mode
Request the heater and controller documentation, firing mode, connected load and input measurements at suitable resolution. Eurotherm describes burst firing as whole supply-cycle firing and non-firing periods. Other controls can operate differently. Do not confuse a control demand percentage with measured electrical input, or assume all proportional heater controls create the same power waveform.
Keep average and event demand together
Hypothetically, a 6 kW resistive load on for half of each repeated period averages 3 kW over complete periods. Its on-state demand remains 6 kW in that idealized case. These invented values omit waveform details and losses. A measurement window covering only part of the period can report a different average, so retain the averaging definition with any demand record.
Retain measurement resolution when sharing a trace with the source designer. A meter that stores only ten-minute averages can support energy totals while leaving the repeated on-state capability question unresolved.
Specify source and dispatch evidence
Ask the electrical integrator to assess repeated additions/removals, acceptable voltage behavior and the selected source's supported duty. Do not infer suitability from a battery energy total or alter firing settings without the responsible designer. Wind allocation may be averaged differently from instantaneous heater input if another approved source balances the difference. Provide both the heat-service objective and electrical event profile in the RFQ. No universal burst period, protective-device choice or MARSTON heater-control capability follows from the general example.
Sources
Examples are illustrative. Confirm product-specific performance, compatibility and supply scope in the applicable documents.