The Nautilus CMC Medium Head (CMC-MH) style turbine has been produced in the U.S. since the early 1900’s. This simple regulated Francis turbine is designed for heads of 3m to 12m and develops a maximum electrical output from 1,900 watts to 9.2 kw, depending on available head.

We have replaced the old style round iron pressure case with a modern stainless steel scroll case to increases efficiency and reduce weight. This improvement still incorporates the simple, strong gate mechanism that has served this design so well in the past. Many U.S. turbine makers used this simple ‘register gate’ design for regulation because it has proven to be durable and only has 3 moving parts.

Over 4000 turbines were manufactured with this type of mechanism and it has performed dependably over many years of operation. This count is from original company records of turbines installed up until 1945 and some of these turbines are over 100 years old and are still operating today. The CMC-MH turbine is designed to be bolted to a 12in penstock and comes with a universal generator mounting plate. The standard CMC-MH is supplied with a 4ft long draft tube so that it can be mounted above tailwater without any head loss. This protects the turbine and generator from flooding.