40,000 CMH · 100 mmWC · 25 HP · belt drive · VFD-driven · hot-start capable
A Maharashtra-based furnace and heat-treatment OEM builds furnaces and heat-treatment lines for a living. When they specify a fan, they are not buying air movement in the abstract — they are buying a component that has to behave inside a hot system, on their schedule, under their controls.
Forty thousand cubic metres an hour at 100 mmWC is high-volume, low-pressure work. That part is straightforward to state and unforgiving to get wrong: at low pressure the fan curve is flat, so small errors in the system resistance move the operating point a long way. Two things made this duty demanding, not routine.
First, the fan has to start against a hot system. Furnace air does not wait for a cold, quiescent start — the ductwork is already at temperature, the gas is already thin, and the motor has to break the impeller away and come up to speed under that condition without stalling or tripping. That is the hot-start requirement, and it is written on the drawing, not added by us.
Second, the fan has to turn down cleanly on a VFD. A furnace line does not run at one point; it ramps, holds, and backs off as the process demands. The fan has to follow the drive down through its speed range and stay in control the whole way — no surge, no hunting, no loss of the operating point.
Belt-drive centrifugal fans, VFD-compatible, hot-start capable — built to the 40,000 CMH / 100 mmWC / 25 HP duty on their fan curve, not to a nearest-catalogue-size approximation. Belt drive keeps the impeller speed independent of the motor, so the fan is selected to the duty rather than to whatever a direct-coupled pole count allows.
Every fan is performance-tested in-house on our 200 HP VFD test rig, to the IS 4894 / AMCA 210 method, before it leaves the works — the VFD turn-down is proven on the rig, not assumed from the curve.
This is not a one-fan story. The supply has run across furnace build after furnace build, multi-year and repeat — the kind of relationship that only holds when the fans keep doing on the line what the curve said they would do on the rig. They keep coming back because the duty keeps being met.
If you build furnaces or heat-treatment lines and you have a fan that has to start hot and turn down on a drive, send us the fan curve and the system resistance. We will select to your duty and prove it on the rig before it ships — proof, not promises.
— Mihir Kulkarni, Director, Jitamitra Electro Engineering
Engineered for Every Application.
No model numbers needed. Give us the operating conditions and our application engineers size the fan and quote it.