Help Please! 7 Watt Coherent appraisal

[buffo]

Bring it to SELEM... I'll bet Steve Roberts could get it working. (Or at least tell you why it won't work...) We've got 450 amps of 208V 3 phase power available at the venue for SELEM this year. More than enough juice to run several lasers like yours. (Yeah, we've got the water flow to support it too.)

Adam

[Things]

Umm 208V? Thats a weird voltage, usually 3 phase is 415V. Oh well I guess us Aussies run straight off 240V anyway

[platinum]

Umm 208V? Thats a weird voltage, usually 3 phase is 415V. Oh well I guess us Aussies run straight off 240V anyway

I regularly run into 208-230v 3-phase on my day job. (HVAC)

Here are the standard voltages for the US:

[Keibot]

Bring it to SELEM... I'll bet Steve Roberts could get it working. (Or at least tell you why it won't work...) We've got 450 amps of 208V 3 phase power available at the venue for SELEM this year. More than enough juice to run several lasers like yours. (Yeah, we've got the water flow to support it too.)

Adam

Adam,
I really have no reason to believe it doesn't work. I ran it right before I bought it and I've seen it run on several occasions. It has been sitting idle for about 8 months though.

[Lasernerd]

I regularly run into 208-230v 3-phase on my day job. (HVAC)

Here are the standard voltages for the US:

Hey Jonathan,
want to build me a 3 phase rotary inverter 10hp. with load balancing bank?
Also looking for a water chiller,like the ones in buildings to cool the water flow on upper floors.

[loopee]

Umm 208V? Thats a weird voltage, usually 3 phase is 415V.

Australian - Single Phase 240V / Three Phase 415
American - Single Phase 110V / Three Phase 208

[quote=Oh well I guess us Aussies run straight off 240V anyway [/quote]

Unfortunately not as it's only single phase

It's not uncommon to convert small three phase fans to single phase by using a capacitor on one phase and an inductor on another. By doing this it changes the phase angle by 90 degree on the different phases.

3
P---[Inductor]----
H |
A----------------o------Single Phase
S |
E---[Capacitor]---

------------------------Neutral

However the current being drawn through a laser is considerably more and therefore I would not think it would be practical (I certainly wouldn't use it on an expensive gas laser, even if I had one)

Troy

[platinum]

Hey Jonathan,
want to build me a 3 phase rotary inverter 10hp. with load balancing bank?
Also looking for a water chiller,like the ones in buildings to cool the water flow on upper floors.

Hmm, sounds like a great opportunity to zap myself. I'll pass.

[buffo]

If you're going to try to run a 3 phase laser off a single-phase source, you're looking at a rotary phase converter. True, for a fan or other small motor you can get by with a large capacitor and an inductor, but the laser is going to draw 30-50 amps per leg!

What you do instead is wire single phase power to a large 3 phase motor, and then use the inductor and capacitor to get power on all three phases so the rotor will start turning. Once it's turning, you'll have 3 phase power on the power input lugs of the motor which you can then power your laser from. (Cool, eh?) There's more to it, of course, but that's the general theory.

Of course, you'll be drawing 100 amps or more from that single phase power source! And you'll have a heavy-ass 20 to 30 HP motor spinning at several thousand RPM sitting on the floor next to your laser. Not the ideal solution, but it's cheaper than getting 3 phase power run in to your garage!

Also, 3 phase "Y" connected power is normally 208 V here in the US, but 3 phase "Delta" is usually 240V.

Adam

[bradstockdale]

There is another, more efficient way, to get 3 phase from single phase... I have used rotary phase converters, and while they work fine (if sized correctly), they are big, heavy, and not very efficient... A better way is to use a Variable Frequency Drive...

VFD's are used mainly to control the speed of motors... They usually take single or three phase input, rectify it, and then regenerate the three phase output at whatever frequency you desire...

I have a 35HP VFD that I use to make three phase power... I put in 220VAC single phase, lock the frequency at 60Hz, and out pops pure sine wave three phase. Yeah, 35HP is overkill for my application, but the price was right and it was brand new in the crate.

The only modification I did to mine was add an extra filtering capacitor after the input rectifiers. The unit already had a place for it; just had to buy one and install it. The manufacturer recommended this modification for my usage... 90% of VFD's can be used as phase converters. The other 10% are not setup to deal with missing input phases (i.e., the uController checks to make sure there is proper 3 phase applied before operating -- too smart for our usage.)

You can find them surplus pretty cheap. They are lighter, more efficient, and more flexible.

Just my thoughts... FYI, I really have never played with diode lasers... I have a family of ion lasers from a small ALC 60X on up to a Lexel 95, with several Lexel 75's and an ALC 909 in between. Not saying I'm an expert on ANYTHING, but I am saying that I have some experience with ion lasers.

Regards,
Brad (Jack of all trades, master of none)

[Lasernerd]

There is another, more efficient way, to get 3 phase from single phase... I have used rotary phase converters, and while they work fine (if sized correctly), they are big, heavy, and not very efficient... A better way is to use a Variable Frequency Drive...

VFD's are used mainly to control the speed of motors... They usually take single or three phase input, rectify it, and then regenerate the three phase output at whatever frequency you desire...

I have a 35HP VFD that I use to make three phase power... I put in 220VAC single phase, lock the frequency at 60Hz, and out pops pure sine wave three phase. Yeah, 35HP is overkill for my application, but the price was right and it was brand new in the crate.

The only modification I did to mine was add an extra filtering capacitor after the input rectifiers. The unit already had a place for it; just had to buy one and install it. The manufacturer recommended this modification for my usage... 90% of VFD's can be used as phase converters. The other 10% are not setup to deal with missing input phases (i.e., the uController checks to make sure there is proper 3 phase applied before operating -- too smart for our usage.)

You can find them surplus pretty cheap. They are lighter, more efficient, and more flexible.

Just my thoughts... FYI, I really have never played with diode lasers... I have a family of ion lasers from a small ALC 60X on up to a Lexel 95, with several Lexel 75's and an ALC 909 in between. Not saying I'm an expert on ANYTHING, but I am saying that I have some experience with ion lasers.

Regards,
Brad (Jack of all trades, master of none)

I am with you! I just started playing with these little Diode things in
the application of laser light shows!still no comparison to the all mighty ION laser!
Would you by chance have any links to the VFD's?