Hoping some one can gave some information on this ,I have a CNC machine runing a Delta VFD-E Series drive for the motor.It runs fine except in the cold weather,purchased in Janurary of this year,on cold days it would stop working during the cut damaging the bit and error code 8888 would show,you could restart the machine and it would run for hours before same thing happened, put a heater close to the cabinet and when temperature increased drive ran fine , spring arrived and heater disconnected no problem now in November problem reaccured heater reconnected and fault does not reaccure, when heater is put near cabinet temperature is raised above ambient temp by a few degrees ie from around 19C to 22 celcius and problem fault does not reaccure