DC motor with power supply

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Foreverof

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Hi guys,

I have a DC motor, 24V, it use 2.4A current when no load, it use 10.4A current when full load. When the motor start, it use 12A to 15A current for start up.

Any suggestions on how I choose my DC power supply?

1) I get a 24VDC and 14A power supply, and it has 120% to 160% of rated load current for overload protection.

2) I get a 24VDC and 20A power supply, and it is double more expensive.

Please help, thanks very much.
 
090507-1015 EST

Foreverof:

If you have a permanent magnet commutator type DC motor, then without going backwards maximum current is when the rotor is locked. This locked rotor current is probably much greater than 15 A. Thus, at initial start the peak current is probably greater than 15 A unless the source limits this.

If you are looking at regulated power supplies, then these almost certainly have current limiting near or somewhat above maximum current rating. How often such a supply can be overload is a function of its design.

Your smaller supply may work. Starting time of the motor may be a major factor. The higher the inertia load the longer is the starting time.

.
 
I pretty much agree with Gar. Locked rotor (armature) on a DC motor can take many times full load current at rated voltage.
A current limiting supply would do the job.
But a word of caution.
Some power supplies have foldback current limit rather than a constant current limit.
 
Thanks for the reply, I was wondering, do you know any current limiting power supply? I am still looking for one.

The one I was going to buy it said this:

Overload Protection
The Power Supply is provided with an overload protection function that protects the power supply from possible damage by overcurrent. When the output current rises above 105% min. of the rated current, the protection function is triggered, decreasing the output voltage. when the output current falls within the rated range, the overload protection function is automatically cleared.

1. Internal parts may occasionally deteriorate or be damaged if a short-circuited or overcurrent state continues during operation.
2. Internal parts may possibly deteriorate or be damaged if the Power Supply is used for applications with frequent inrush current or overloading at the load end. DO not use the Power Supply for such applications.
 
if it is just a regular old DC motor your best bet is probably what used to be called a brute force power supply.

Not much more than a transformer,a bridge rectifier, and a capacitor. regulation is not typically an issue with a motor load. if it is off a little, it just doesn't matter a whole lot.
 
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