Yes, it is possible to use a single-phase generator to power a 3 phase energy meter. This can be done by using a phase-shifting transformer or a phase-shifting device to shift the phase of the single-phase generator's output so that it can be used to power a three-phase load.

However, it is important to note that a single phase meter will not be able to produce a balanced three-phase power supply, so the meter may not provide accurate readings in this situation. Additionally, the phase-shifting transformer or device will introduce some loss in the power supply, which may affect the accuracy of the meter's readings.

It is generally more efficient and cost-effective to use a three-phase generator to power a 3 phase energy meter, including a three-phase meter. This is because a three-phase generator is designed to produce a balanced three-phase power supply, which can be used more efficiently by three-phase loads.