What is the allowable voltage variance for a furnace blower motor rated at 230 V?

The allowable voltage variance for a furnace blower motor rated at 230 V is typically +/- 10%. This means that the motor can function effectively within a voltage range from 207 V to 253 V. This tolerance is essential for ensuring optimal performance and efficiency. Operating outside this variance can lead to overheating, reduced lifespan, or failure of the motor.

The +/- 10% variance standard is based on industry recommendations, ensuring that motors can handle fluctuations in voltage that may occur in residential electrical systems. Systems that only specify a lower variance, like +/- 5% or +/- 8%, might restrict performance too tightly and could result in more frequent issues due to minor electrical variations commonly found in everyday environments.

A variance of +/- 15% is generally considered too wide for most HVAC applications, as it increases the risk of potential damage to the motor and could lead to operational inefficiencies. Thus, the choice that reflects the acceptable performance range for a 230 V furnace blower motor is the +/- 10% variance.