Solar power to Invertor

[dickieus]

I have been handed a project where "they" want to power an amusement ride with solar a solar oower array. The ride currently has a 5hp sumotomo AF502 220 3ph invertor. The available power is 220 single phase. Changing the motor is not an option as it is motor gearbox combination. what I am looking for is the best option to replace the invertor.

 

[leitmotif]

I am going to do something similar ie use three phase motor - 50 HP to drive a pickup truck using VFD and a battery.

No matter how you do this there are some hoops to jump.
In essance you tie the DC from your solar cells direct to DC bus of inverter. Simply said NOT simply done.

You do not want to change the motor.
That means you will need a 325 (about) VDC line voltage to inverter. You may not be able to get solar cells in enough quantity to be able to deliver the voltage and amperage demanded by motor. However you could use a battery which would supply the current of the motor. You would also need a battery when you operate at night unless you tie into a generator somehow - again more complexity. Solar cells would recharge battery between operations - this will take some calculations to ensure you allow enough recharge time
PLUS 30% approx - battery charge "overhead".

You may have to replace the inverter since it may be hard to physically connect conductors to DC bus. Hitachi SJ 300 have the ability and directions on how to do this. Allen Bradley makes a VFD designed just for this purpose. I would recommend this one for following reasons
1. It has precharge built in. You will need this to protect capacitors in VFD especially so if you are starting off a battery. You may also need the caps to allow time for EEPROM when you deenergize.
2. If you go battery route then you can remove dynamic braking resistor - the battery will replace that.
AB unit has no dynamic brake resistor.

The other option is to drive a 3 phase inverter off the solar cells and either do across line starting OR feed the 3 phase to the VFD (or just single phase inverter to feed VFD if you want). The advantage to this is you can do with 24 or 48VDC. I am not sure about driving a VFD off an inverter - you may need to spend the bucks and get a "true sine wave output" inverter.

This is gonna get a little pricy. I support the thinking and offer an alternative. Solar charge the battery during the daytime and run lighting off battery at night. The big advantage here is you do not need the 325 VDC bus you could easily do this with 24 or 48 VDC. If you want to run 120 VAC lighting and especially so for fluorescant you will need an inverter. Do not forget to get a little icing on cake and see if you can get a government grant tax reduction for this.

Dan Bentler

 

[dickieus]

Thanks for the reply. I have thought about the dc bus connection. the company that is suppling the solar power is sending a trailer mounted unit for me to see on monday. According to the engineer I talked to they have invertors on the system that develop 220vac. they have 3 legs but it is not a true 3 phase. They have a set of 48 volt batteries to sustain an ballast the system. So what I think I am looking for is a 220 single phase to 3 phase convertor. I will know much more when I see the system.
P.S. This should not be a suprise but we are in California.

 

[leitmotif]

IF they have an inverter with single phase 220 you are in buisiness. If it is a 220 3 wire Edison (120/240) even better you have more ability to drive differing load types. You already have teh single phase to 3 phase converter ie the VFD.

Dan Bentler

 

[Lancie1]

So what I think I am looking for is a 220 single phase to 3 phase convertor.

There are plenty of VFD's that offer single-phase power IN but 3-phase motor power OUT.

 

[leitmotif]

I have been handed a project where "they" want to power an amusement ride with solar a solar oower array. The ride currently has a 5hp sumotomo AF502 220 3ph invertor. The available power is 220 single phase. Changing the motor is not an option as it is motor gearbox combination. what I am looking for is the best option to replace the invertor.

So what did you find out??

Dan Bentler

 

[dickieus]

I just finally got s look at their system today. What they have is 3 seperate invertors producing 220 vac each. The outputs available are 3 120vac 20 amps and one 50 amp 220vac. I have some pictures. What I am working on now is using the sumitomo invertor on single phase. The problem with that is that I would only be getting 2/3 of the power and still need the 5 hp. My other option is changing the invertor. without becoming a commercial can anyone reccommend a good reliable convertor.

 

[dickieus]

By the way to leitmtiff, they are working on a 3 phase invertpr system
Their builder is Xantrex

 

[dickieus]

Also in the mix is the lighting and control systems. The lights have been cahanged to LED which greatly reduces the load but is on a 220 split. The control is done with a micrologix 1000 which has a dedicated circuit. This should not be a problem as I can sepertate the systems.

 

[dickieus]

pictures

 

[Lancie1]

The problem with that is that I would only be getting 2/3 of the power and still need the 5 hp.

It is not clear what you are talking about. If you only need 3-phase 240 volts for the ride motor, then you do not need another inverter. What you need is a Variable-Frequency Motor Drive, a special-purpose electronic device that is designed to take an AC input, convert it to DC, then converts the DC to AC by rapid transistor switching, to produce a syhthensized variable AC output, either 1-phase OR 3-PHASE. If you mean that you need to convert single phase 240 volts to 3-phase 208 volts, then buy a 7.5 HP. variable speed drive, with the option for 1-phase IN, 3-phase out, and you should have enough power (2/3 of 7.5 = 5 HP) to run a 5 HP. motor. The properly-chosen VFD will run off your existing 50 Amp 240 volt inverter to produce 3-phase 240 volts AC power for the 5 HP. motor.

The ride currently has a 5hp Sumotomo AF502 220 3ph invertor.

I seriously doubt that. True 220 volt 3-phase power is very rare. It might be 3-phase 208 volts, or 3-phase 240 volts. I also question if your 1-phase inverter output voltage actually measures 220 volts with a voltmeter.

1-phase 220 volts in the U.S. is the minimum nominal equipment voltage, the lowest voltage for which a piece of equipment must be designed to operate. Usual actual supply voltage ranges from 240 to 250 volts 1-phase AC. If your inverter is only producing 220 volts, then it output badly needs adjusting upwards. Running any motor at 220 volts is aksing for trouble. The current will be high, causing overheating of the motor, the wiring, and the contactors.

 

[leitmotif]

From some looking into solar and inverters and a 3 phase weil pump I think I know a little but do not understand all.

Let us define terms first.
Converter changes AC to DC
Inverter changes DC to AC come in varying DC volt (supply) and varying AC output both single phase and 3 phase.
VFD (variable freq drive) is special power supply to drive 3 phase motor at varying speed. Come in 3 "flavors" direct tie to DC supply, single phase and 3 phase supply.


Xantrex in the residential line takes 12 or 24 or 48? volt DC to to single phase 120 and maybe single phase 208 or 240. They also take 3 120 V units somehow tie them together to output 208 3 phase.

My guess is the 3 phase units are the Xantrex you show in the photos.

You already have the VFD and it is single phase either 208 or 240 to drive the 3 phase motor.

What you need to do is
1. Verify what input power the VFD must have ie single phase 208 or 240.
2. Get an inverter fed from solar to drive VFD at that voltage.
3. Make sure that solar cells and inverter have enough power to drive the motor and other loads you desire. You may need a battery to handle surge loading.

Based on the display unit these guys are not showing you some little dinky tinker toy setup. I think you are in good hands.

Dan Bentler

 

[timbo_uk]

I have been handed a project where "they" want to power an amusement ride with solar a solar oower array. The ride currently has a 5hp sumotomo AF502 220 3ph invertor. The available power is 220 single phase. Changing the motor is not an option as it is motor gearbox combination. what I am looking for is the best option to replace the invertor.

OUCH, do they have any idea of how much that could potentially cost. Do you know how many hours per day the ride needs to run?

without lighting thats around 20kVA.

That will need some serious battery capacity, I would do some calculations first and see what that will cost, then add for the solar array.

I would suspect that "they" may fall off the chair when you give them an idea of cost.

 

[leitmotif]

It is not going to be cheap that is for sure.
What "they" are going to have to do is not look at the installation cost but look at life cycle cost.

Present costs
Utility hookup
or running own generation fuel cost, maintenance, repairs, fines for smoky exhaust, noise violations, replace generator unit, etc

Solar costs
Repair to cells and or inverters. Fuel costs if forced to generate (nightime, breakdown etc)

Dan Bentler

 

[dickieus]

ok so what I really need is a reliable 7.5 single to three phase inverter. I have had some bad experiences inT the past with these.
The AF 502 has been obsolete for at least 10 years so don't want to mess with it as parts are rare, especially the power transistor.
I know it's not cheap, especially for a temp conversion, but what they want is what they get. The unit shown has a 48 volt battery array for backup. also they are going to add a propane generator for night use