MCT8329A: MCT8329A - Maximum supported BLDC Motor RPM

Karthikaichelvan Eswaran

Part Number: MCT8329A

Tool/software:

Hi,

I am using MCT8329A part for controlling my BLDC motor.

The Spec of the Motors are

Voltage: 14.8V
KV: 3650KV
Configuration: 9N12P (12 Poles)

Since it is mentioned in datasheet that the maximum electrical frequency supported by MCT8329A is 3KHz, then according to the calculation of mechanical speed

Mechanical Speed (RPM) = F(elec) * 60 / Pole pairs.

Given:

F (elec) = 3 KHz; Pole pairs = 6 then,

Maximum Mechanical speed = 30,000 RPM.

So by this can we confirm that MCT8329A supports a maximum of 30000 RPM? If not, please let me know what the maximum supported RPM is.

3 months ago

0 Venkatadri Shantaram84961 3 months ago

TI__Mastermind 23662 points

Electrical 3KHz can be any RPM based on the pole pair combination, MCT devices supports upto 3KHz which can be 30kRPM.

What is the BEMF constant of the motor?

What is the rated current at 3KHz under rated load?

Thanks and Best regards

Venkatadri S

0 Karthikaichelvan Eswaran 3 months ago

Prodigy 20 points

Hi Venkatadri,

Please find the specification of my motor in the below attachment.

For ~30000 RPM (@ 3KHz Fsw) the maximum current drawn is 19.6A.

I don't have data for BEMF constant.

0 Venkatadri Shantaram84961 3 months ago in reply to Karthikaichelvan Eswaran

TI__Mastermind 23662 points

Thanks for sharing, I will verify this and get back by tomorrow.

Thanks and Best regards

Venkatadri S

0 Karthikaichelvan Eswaran 3 months ago in reply to Venkatadri Shantaram84961

Prodigy 20 points

Hi Venkatadri,

One more query on electrical frequency

As you see in the attached image the MAX_SPEED field is a 16-bit field

if MAX_SPEED = 0xFFFF then the decimal value will be 65,535

So according to this the Maximum electrical speed supported is 4095.9 Hz. With this data can we conclude whether MCT8329A can support up to ~4KHz of electrical frequency?

0 Venkatadri Shantaram84961 3 months ago in reply to Karthikaichelvan Eswaran

TI__Mastermind 23662 points

It is verified for 3KHz max and beyond that other factor matters.

Even though register field can accept 16-bit value.

Thanks and Best regards

Venkatadri S

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MCT8329A: MCT8329A - Maximum supported BLDC Motor RPM