Letter to the editor: Controlling heat8 December 2004
In the October/November issue of Hoist magazine, the article ‘Controlling Heat’ (pp27-33) accurately explains how to calculate the heat generated by digital DC drives and how to manage the heat generated by using such thermal management solutions as air conditioners, air vents, heat exchangers, vortex coolers and heat pipe liquid cooling techniques.
As the originator of digital DC drive technology and the leader in the field of digital DC drive technology, Cableform has avoided the thermal issues associated with the drives, and similar drive topologies, referenced in Mr. Urbassik’s article.
Mr. Urbassik’s heat generation calculations all seem to be correct. The difference between Cableform’s patented LMC digital drive designs and those drives referenced by Mr. Urbassik, however, lies in the Watts per Amp data of Figure 4. These Watts/Amp constants listed in Figure 4 are, as described, the power losses associated with the drive circuit.
The Watts/Amp constants associated with the patented Cableform LMC circuit designs, in comparison, are approximately a third of the magnitudes listed in Figure 4. Therefore, the heat produced within Cableform LMC drives is about 66% less than the heat generated by the drives utilized in Mr. Urbassik’s article.
The result is that if the heat is not generated, then it does not require managing. Cableform’s LMC crane controls are utilized without the need for costly thermal management solutions in applications up to 300HP.
-Andrew Thexton, Vice President, Cableform