AC Drives

I doubt it. What would guarantee that the two drives would produce exactly the same frequency output?

Why do you want to have 2 drives?

Redundancy?

Explain your reasoning please.

why would you consider this?????????????

Wow, what are you thinking this christmas? Planning to self destruct your companies asset? Its okay if its yours, well go ahead and see if it works be sure to compute your safe distance while doing it.

Dont think while drinking.it will end up a mess. May be its just the beer, don't you think?

It sure sounds like a bad idea. Not only would the voltages have to be matched so that they share the current, but the phases have to be matched also. Don't do it unless the drives are designed for it.

I never seen one application of paralled drive Rix, by the way.

Not really. Your proposal smacks of complete nonsense.

Two for one sales are not always a good bargain.

Parallel converters are often used in high HP low voltage drives. I am talking drives for 300Hp and up. The bridges are specifically designed to run in parallel, with some awfully smart circuits in behind them to guarantee load share, voltage match , and frequency.

For your size application taking a couple standard drives and just hooking them up will risk letting out all the smoke that has been built into them. They were not designed to be run in this manner.

What you mean to say is double inverter (Inverter DC-AC) unit in one controller as one module, it is applicable.

Problem is if you have two parallel typical module in one motor (load). System feedback will be different at some degrees for the 2 modules. Output Synchronization will be a problem having 2 separate controller-inverter modules. Below is the wiring diagram for reference.

Short answer: No, you cannot.

In order to do that, the output of both drives need to be synchronized, not just in frequency but also in phase. To do that, they need to be connected together in something like a master-slave fashion so that one drive is always copying the other's output. I know of no drive that has that feature. I'm not saying there aren't any such drives but I just don't know about them.

It seems you've got an application where you need to control the speed of a 55kW motor but don't have a 55 kW drive but you do have two 30 kW drives. Nice idea but won't work.

regards,

Vulcan

A good follow up question on this is, could there be a power amplifier to boost output current from the inverter, or is there any means or product on the market for this application 55kW load. I bet OP should ask the product technical sales on this for a solution.

It is n fact a very common practice to use parallel inverters on large drives in order to provide what is called "N+1" redundancy, wherein if one output module fails, the VFD keeps operating the motor at 1/2 capacity (by reducing the speed). But that is a very complex application and those inverters are designed up-front to operate in this way, it involves using a fiber optic interface to each inverter firing module in order to accomplish noise-free synchronization. Without that, the drives will destroy themselves. That capability is expensive, but amortized out into the high cost of 500kW and larger VFDs, makes little difference. You will not find that capability in an off-the-shelf 30kW drive.

There was, for a short while, a small drives mfr in the US called Vee-Arc that made a small drive capable of being paralleled into larger units. But they were too expensive. Vee-Arc was owned by Furnas Electric, who was bought by Siemens and although technically Siemens now owns the patents to the technology, they determined it was not a viable product for the market, because nobody would pay that much extra for that capability.

Dear Mr.VIKAS

Theoritically the answer for your question is YES.

BUT IN PRACTISE - It is not advisable - for 2 reasons.

1. The V/f Ratio may not be the same.

2. Any difference in the Voltage will induce LARGE CIRCULATION CURRENT, resulting in Over-Heating of Motor Windings.

DHAYANANDHAN.S

Most certainly not !THere is no way to ensure, same voltage, same frequency and same phase output.

Don't be silly.