Generator / motion labs conflicting stories... Help!

[Shane Presley]

I just setup at a gig.. Generator 25kw set to single phase to my motionlabs 3 phase panel with metering. I fired up the gene and my panel... It's showing 118-120v on red and black, and 60.1hz. Now this is where the fun begins. I plugged in my ups for my digital console and the hz reading on the motion labs goes anywhere from 60 to as much as 150hz! Voltage is stabe, voltage showing on ups is fine, analog voltage meter on gene is rock solid, no motor fluctuation either... Solid. I'm trying to figure out if my motion labs display is having issues or what. I have a guy I trust coming out early tomorrow am to check everything over, and he has a fluke to measure hz. Anybody have any suggestions... Btw it's not just the ups, throwing it into a tizzy, as some as I start to apply load, the hz swings wildly.. But no motor revving on the geny
Any ideas?

 

[Chris Greco]

Re: Generator / motion labs conflicting stories... Help!

How are you hooking up a 3 phase distro to a single phase genny? If the meter panel is not seeing three hot legs then thats probably where the issue is. I would meter with a VOM and be careful with they way you hook up your distro. In a perfect scenario you should be using a single phase distro with your single phase genny.

Right tools for the right job

 

[Rob Timmerman]

Re: Generator / motion labs conflicting stories... Help!

Unless the generator has an inverter output (unlikely), the output frequency will be a function of the generator RPM. So if the generator speed isn't fluctuating, neither is the frequency. What have you been using for loads? Last I checked, the Motion Labs meters weren't reliable under about 10A, and it's quite possible that the frequency measurement is being confused by distortion on the waveform (THD from power supplies). Any chance you can test with something "well behaved" as your load, such as a filament lamps (PARs, work lights, whatever)?

 

[Shane Presley]

Re: Generator / motion labs conflicting stories... Help!

How are you hooking up a 3 phase distro to a single phase genny? If the meter panel is not seeing three hot legs then thats probably where the issue is. I would meter with a VOM and be careful with they way you hook up your distro. In a perfect scenario you should be using a single phase distro with your single phase genny.

Right tools for the right job

I brought a 3 phase distro cause I was told the geny was 3 phase... The electrician gave me the bad news when he grabbed my tails . My motion labs is marked as to which 30 amp twists are live when using single phase. I temporarily fed the blue leg off the red phase to see if that was the case ...no load... It didn't remedy the issue.

 

[Shane Presley]

Re: Generator / motion labs conflicting stories... Help!

Unless the generator has an inverter output (unlikely), the output frequency will be a function of the generator RPM. So if the generator speed isn't fluctuating, neither is the frequency. What have you been using for loads? Last I checked, the Motion Labs meters weren't reliable under about 10A, and it's quite possible that the frequency measurement is being confused by distortion on the waveform (THD from power supplies). Any chance you can test with something "well behaved" as your load, such as a filament lamps (PARs, work lights, whatever)?

The electrician returned the following day with a fluke that showed hz and waveform... All was well, I suspect as you say, under the 10 amp draw, it wasn't indicating properly cause after I fully fired up, it got stable , the hz reading was correct. We did try a couple pars, and a buddy of mine said to use the flourecent lighting on the stage to act as an indicator if power is wonky... He said they will usually freak out if power is bad. Anyway, turns out I was worried for nothing, but if it one thing I respect is power... I've been burned once (not me, but my stuff got smoked when another tech hooked up without metering and blew my ls9 and a driverack 480 etc... I wasn't about to lose gear on MY watch.

 

[Chris Greco]

Re: Generator / motion labs conflicting stories... Help!

The electrician returned the following day with a fluke that showed hz and waveform... All was well, I suspect as you say, under the 10 amp draw, it wasn't indicating properly cause after I fully fired up, it got stable , the hz reading was correct. We did try a couple pars, and a buddy of mine said to use the flourecent lighting on the stage to act as an indicator if power is wonky... He said they will usually freak out if power is bad. Anyway, turns out I was worried for nothing, but if it one thing I respect is power... I've been burned once (not me, but my stuff got smoked when another tech hooked up without metering and blew my ls9 and a driverack 480 etc... I wasn't about to lose gear on MY watch.

Shane,

I contacted my buddies over at Motion and explained what you were experiencing and they are going to rent a single phase genny and try to replicate your problem. They did say that on their meter panel that is currently in development, it will have the capability to be switched into a single phase mode. I will let you know what they find out.

 

[Shane Presley]

Re: Generator / motion labs conflicting stories... Help!

Shane,

I contacted my buddies over at Motion and explained what you were experiencing and they are going to rent a single phase genny and try to replicate your problem. They did say that on their meter panel that is currently in development, it will have the capability to be switched into a single phase mode. I will let you know what they find out.

Ok great, glad to see some good come from this. To be fair I have an "older version" of thier distro, so hopefully it wasn't that. Like I say, after things got fired up... It was more stable. I should have taken video...

 

[Chris Greco]

Re: Generator / motion labs conflicting stories... Help!

Ok great, glad to see some good come from this. To be fair I have an "older version" of thier distro, so hopefully it wasn't that. Like I say, after things got fired up... It was more stable. I should have taken video...

I was one of the 3 founding members of Motion Labs so I still have an interest and personal obligation in things with them being right. The meter panel has gone through some serious changes and the new version will be electronically advanced with more functionality than the early versions. Now thats not to say that the earlier ones didn't do the trick, its just that as with most things, as time & technology march on sometimes shortcomings that weren't initially noticed, rise to the surface. The take away here is that the shortcomings are being addressed and improved. Stay tuned

 

[TJ Cornish]

Re: Generator / motion labs conflicting stories... Help!

I was one of the 3 founding members of Motion Labs so I still have an interest and personal obligation in things with them being right. The meter panel has gone through some serious changes and the new version will be electronically advanced with more functionality than the early versions. Now thats not to say that the earlier ones didn't do the trick, its just that as with most things, as time & technology march on sometimes shortcomings that weren't initially noticed, rise to the surface. The take away here is that the shortcomings are being addressed and improved. Stay tuned

That's interesting. Is the new meter module months away, or years? Any plans related to expanded GFCI requirements? The site still appears to be the same as it was a couple years ago.