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View Full Version : Help needed identifying this DC motor Specs



simonl
6th Dec 2017, 03:23 PM
Hi all,

I'm in need of a replacement DC motor for a small 12VDC hydraulic pump which i plan on using as the log lifting system for my hydraulic log splitter. The pump was originally used on my hydraulic press but i burnt the motor out.

I have a smaller 24VDC motor which "may" do the job. Even running on 12V it may still generate enough pressure to lift heavy (to me) logs. The pump can produce over 3000 psi but i doubt it will need to produce anymore than maybe 500 psi, depending on the log, the ram used and the placement of the ram.

Anyway, the intended motor i have has a nameplate thag i find rather confusing.

It states 24VDC and 450W but also 4.5A max.

However 4.5A @24VDC is only 108W.

108W will definately not be enough.

Any help on watt (pun intended) the max power of this motor is @24VDC is much appreciated.

Cheers

Simonhttps://uploads.tapatalk-cdn.com/20171206/785ddd1eea2c9456fe52f1518d03de3b.jpg

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BobL
6th Dec 2017, 04:28 PM
The 4A will be a no-load current - these things will draw ~20A when they are loaded.

simonl
6th Dec 2017, 05:12 PM
Thanks Bob. I wondered if that was what it meant but i have (in my limited experience) never seen a spec with a no load current listed on the name plate.

Simon

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jhovel
6th Dec 2017, 08:31 PM
108W? huh? :?

96W ISO (24Vx4.0A) = exactly 450 W C.W (Chinese Watts).....it says so on the label.....:hpydans2:

BobL
6th Dec 2017, 09:22 PM
I suspect the unloaded current is provided so they don't rev themselves to pieces.

Here's a typical spec for a similar motor from https://www.motiondynamics.com.au/my9764-450w-24v-dc-motor.html
371317

1 Nm = 0.74 ftlbs which at 4500 rpm is equivalent to 0.74 x 4500/5252 = 0.63 HP = 470 W

jack620
7th Dec 2017, 05:37 AM
I suspect the unloaded current is provided so they don't rev themselves to pieces.


What do you mean by that Bob? Surely the unloaded current "is what it is". Are you suggesting some sort of current limiting needs to be provided to keep the unloaded revs down?

BobL
7th Dec 2017, 09:38 AM
What do you mean by that Bob? Surely the unloaded current "is what it is". Are you suggesting some sort of current limiting needs to be provided to keep the unloaded revs down?

I was just wondering if some folks might be tempted to apply more than 24V ?

simonl
7th Dec 2017, 04:26 PM
Thanks Bob for your help. Oh yes, specials thanks goes to Joe for his helpful comments and edumacating me on the concept of CW, "Chinese Watts". I'll keep an eye out for future references to such electrical specs! :2tsup:

Simon