The formula to obtain the hysteresis loss devised by Steinmetz is:

[ W_h = k_h cdot f^x cdot B_{max}^y ]

where:

– ( W_h ) is the hysteresis loss in watts per cubic meter of the material,

– ( k_h ) is a constant specific to the material,

– ( f ) is the frequency of the magnetic field in hertz,

– ( B_{max} ) is the maximum magnetic flux density in tesla,

– ( x ) and ( y ) are empirical constants typically found through experimentation (commonly, ( x ) is taken as 1.5 and ( y ) is around 2.0 for many materials).

To account for additional iron losses in DC machines, the following steps can be undertaken:

1. Measure and Determine Iron Losses: Identify the core material and measure the core losses (hysteresis and eddy current losses) at varying frequencies and flux densities.

2. Adjust Parameters in Design: Incorporate the measured iron losses into the design calculations. This may involve selecting appropriate core materials and optimizing the machine geometry to minimize losses.

3. Use Loss Models: Implement loss models that take into account both hysteresis and eddy current losses for accurate predictions based on the operating conditions.

4. Increase the Efficiency of Core Material: Select high-quality magnetic materials to reduce hysteresis losses and optimize lamination thickness to minimize eddy current losses.

5. Test and Validate: Conduct tests on the prototype or the designed machine to validate the iron loss calculations and make necessary adjustments in the design or operation parameters.

By including these considerations, you can effectively account for additional iron losses in DC machines.