Driving Multiple Coils with SINAMICS v20

Hello everyone,

We have a SINAMICS V20 in our group, for a research project, we are trying to drive 12-15 Hz ac through multiple coils. We tried to utilize SINAMICS V20 for this but we couldn't succed. Is there any way to utilize SINAMICS V20 for this kind of task?

Best Regards.

This should be possible; take account of the coil impedance, and the current which will flow.

The V20 may be showing fault  and alarm codes, which should give a clue to what is going on.

A connection drawing with some values would help here.

Dear Sir,

The V20 always giving a F1 error. We checked all the parameters, all our connections and the error still continues. Do you have any further suggestions?

F001, overcurrent.

The coils may have a low impedance, can the turns be increased?

Or; increase the frequency to 50Hz, in order to see if the V20 will supply the coils without overcurrent trip.

The impedance of the coils will vary according to the frequency supplied. (XL=2pifl, ‘cool’ huh)

Consider; the V20 will supply the frequency with a fixed frequency to Voltage ratio. I am sure we can reduce the voltage supplied to the coils, by connecting an analogue input to set the Voltage lower than it would normally be. This can be done with a Micromaster MM440, so I need to go away and look into this with regard to the V20.

Standby....

The output Voltage of the Micromaster 440 can be linked to the analogue input, making the Voltage adjustable using a potentiometer.

Now, the V20 is very similar so, see if you can find P1330. If you can see this parameter make it equal to r755. (P1330 = r755).

N.b. Set P0003 to 3 (expert), to be able to see all parameters.

The analogue input 0 will then be able to set the V20 Voltage, then find ‘empirically’, the Voltage which respects the impedance of the coils which you are using.

Another ‘trick’, may be to set P310 (motor rated frequency) to a high value, say 100Hz, this will distort the V/F (Voltage to Frequency relationship). Which means the V20 output Voltage will not achieve line Voltage until the frequency reaches 100Hz. For your evaluation 15Hz, the Voltage out from the V20 will be quite low.

I do not have a V20 to work with here, it would be good to be able to test this for you, so see how you get on.

Come back if I can help further......

Dear sir, at this point we see no error or alarm codes on the device. The problem is, we need to drive coils with at least 1 amps to achieve required magnetic field. When we start driving the coils, the device shows only 0.05 amps passing through (although we set parameters to give 1 amps). We increased the voltage about half of its value but it didn't work, we reach 0.05 again (and power resistors get very hot). What is your opinion about this problem? Thanks for your time in advance.

If I understand the application correctly; you have set the frequency in the region of 15Hz, the Voltage applied to the coils can be adjusted by setting a higher or lower frequency in P310.

The impedance of the coil will be a function of frequency applied, and the resulting current flow will be proportional to the applied Voltage. This should provide what you need to energise the coils in a controlled way.

I am not sure now where the resistors come into the application??

A circuit would be useful, in order to see how the application is connected. 

What we have is a very simple circuit. We are inexperienced using any sort of vfd. Apologies.

We are not sure of the methodology the device follows in generating the current. Does it supply the current specified in p305 unless the voltage limit is crossed or does it apply the voltage specified in p304 unless the current limit is crossed ??