Sizing a Power Supply for a Gear Motor

Thread Starter

ShopRat59

Joined Nov 27, 2013
56
I need help sizing a 24V power supply for a gear motor that will drive an aquarium pump: http://www.ebay.com/itm/Pittman-GM9...-MOTOR-Cole-Parmer-Pump-7016-20-/272279426398

The current specs for the motor are as follows:

Current @ Continuous Torque: 1.82 A
No-Load Current: .16 A
Peek Current: 9.64 A

The detailed spec sheet is at: http://www.pittman-motors.com/Brush-DC-Motors/9236-Brush-DC-Motor.aspx

If the above information is insufficient to answer my question please let me know what data you need, I have the pump in hand and can hook it up and test as needed.

Thanks in advance,

Tom
 

MaxHeadRoom

Joined Jul 18, 2013
24,993
I would use a 24vdc 5a supply, there is very little difference in size or cost of trying to tightly size any supply for a motor.
Regulated or un-regulated will do the job.
Max.
 

Thread Starter

ShopRat59

Joined Nov 27, 2013
56
Thank you for the quick reply - I was sure I didn't need to size it to peak current - but was unsure how far below I could go. In the past I have sized to stall current, but the spec sheet did not include that information.

Could you explain how you came up with 5 amps, calculation or rule of thumb?

Tom
 

MaxHeadRoom

Joined Jul 18, 2013
24,993
Rule of thumb.
If you want to calculate the stall current or the resistance of the motor, you lock the shaft and apply a known low voltage while reading the current.
Try more than one stalled spot and take the highest current reading.
Do not use a Ohm meter.
Normally the supply only sees this Very briefly at switch on, unless an actual stall takes place.
Max.
 

blocco a spirale

Joined Jun 18, 2008
1,546
Be careful if you choose a regulated 5A power-supply as the starting current may exceed this and cause it to shut down. A simple unregulated supply (transformer-rectifier-capacitor) is probably the best choice for powering a motor.
 

MaxHeadRoom

Joined Jul 18, 2013
24,993
As @blocco a spirale indicated, a linear supply is the far better choice for motors, those of which are far more giving when used with a direct-on motor starting.
I generally use a rule of thumb of 2x continuous rated current.
I prefer the linear type, even when a motor controller/driver is used.
Max.
 

MaxHeadRoom

Joined Jul 18, 2013
24,993
Most local electrical suppliers have 120v/24v control transformers, with one of these, all you need is a bridge rectifier, no cap needed for a DC motor.
Max.
 
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