Electric motor driven hydraulic pump

Mark, how can I examine the quality of 3 phase power supply of electric motor driven pump, as I believe poor quality power has made pump faild building up sufficient pressure to retract main gear

We don't normally check power "quality". You can look at it with a O'Scope, but that's just going to show a sine wave.

You have three sources of power on the 737. Each engine driven generator and a  APU generator. These can be isolated to power the complete aircraft if you wanted to try each one individually.

On a previous post I sent a copy of the maintenance manual that stated the electrical pump can "only" supply six gallons a minute and it is "not" recommended for raising the gear. The manual stated it can raise one gear at a time when the aircraft is on jacks.

What is the problem here??? Is a engine pump not working??? Crews are not supposed to use the electric pump for raising the gear. After takeoff, the gear should go up quickly as they cause significant drag. I haven't dug into (nor will I) if either primary hydraulic system can be used to lift the gear.

If an aircraft cannot lift the gear with the engine pumps..... it should be grounded until fixed.
  
     

You're travelling down the wrong road with your thinking.

Mark, My question is not specifically about 737 model, the issue was experienced in F27 Mk0050 for which hydraulic pressurization by electric motor driven pump is an approved ICA without any limitation so that you should normally expect both main gears and even nose gear retract simultanously , so I am asking in general whether three phase supply power quality can affect the performance of electric motor driven pump, regardless of airplane type and model?
I have just emailed MM pages.......

We still don't think in terms of "quality". A electric pump can either do the job or it can't. If you've changed the pump and still have the same issues, you could have a electrical issue or possibly an hydraulic power output issue.

Has anyone done the simple stuff? Are all three phases there? Have you put an Amp Clamp on each phase to make sure they're pulling the same amps? Have you tried another source of power input?

These are basic things to check. Don't think in terms of quality..... try quantity (amperage power).