In the heat input formula, what is the role of the 60 [sec/min] term?

• A. Converts seconds to minutes
• B. Represents efficiency
• C. Converts minutes to seconds
• D. Replaces travel speed

Answer: (A)

Heat input calculations require consistent time units because power is energy per second while travel speed is length per minute. The 60 [sec/min] factor is a conversion between those time bases. Multiplying the welding power ( volts × amps, i.e., watts ) by 60 converts that power into energy per minute, and then dividing by travel speed (inches per minute) gives energy per inch—the heat input per unit length. In other words, it converts minutes to seconds to align the time units.

Note: the intended effect is converting minutes to seconds (since there are 60 seconds in a minute). The option wording may seem to imply the reverse, but the practical role is that time-unit conversion to keep the units consistent. The other choices don’t fit because this factor isn’t about efficiency, isn’t about replacing travel speed, and isn’t substituting any other variable.