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I have a GPN6145A switch mode power supply.

My understanding was that this was a 10A power supply for a CDM1250 and other Motorola mobiles.

However, the sticker on the base of the PSU states 13.8V 2A/4 minutes or 10A/ 1 minute.

While I can understand that the PSU will not supply 10A continuously, I would have thought that , given the size of the power supply (approx 8x6x3 inches), that it would easily supply 2A continuously NOT just for 4 minutes.

You can buy small cheap switch mode PSU's for laptops and LCD TV's etc that will easily supply 2A continuously - so why will a GPN6145A only supply 2A for 4 minutes?

Any thoughts?

Is it safe to use a Motorola GPN6145A switch mode power supply to run at, say 1.5A continuously?

Any ideas?

I have now established that the GPN6145A is also known as a GPN6133A

I have some info which indicates that the GPN6133A will supply 13.8V @6A

Operating load conditions from the spec sheet are: Duty Cycle 4 minutes @ 2A and 1 minute @ 10A OR 3.6A DC Output Continuous.

So the PSU will supply 3.6A continuous BUT 2A for only 4 minutes....this does not make sense??? Any thoughts?

g8tzl2004 wrote:I have now established that the GPN6145A is also known as a GPN6133A

I have some info which indicates that the GPN6133A will supply 13.8V @6A

Operating load conditions from the spec sheet are: Duty Cycle 4 minutes @ 2A and 1 minute @ 10A OR 3.6A DC Output Continuous.

So the PSU will supply 3.6A continuous BUT 2A for only 4 minutes....this does not make sense??? Any thoughts?

I have never seen either one of those but i do have an HPN4002B which is listed on the label as supplying 14VDC @ 10A.

What do these look like?

They look similar to the HPN4002 but do not have an on/off switch on the front.

Search on Google Images under GPN6133A for some pics.

g8tzl2004 wrote:They look similar to the HPN4002 but do not have an on/off switch on the front.

Search on Google Images under GPN6133A for some pics.

I did find it but it is not the same as the HPN4002 - nothing like the one I have.

That looks closer to an Astron built supply, but it is definately a 10A max supply per
the 12V side fuse holder labeled at 10 amp.

I think that rating that is on that label is primarily to keep the supply in the proper
temperature range so as not to over heat the unit.

How much power output (wattage) is the radio you want to use it with? If it is a 25W
radio I'd say go ahead and use it as it should not be a problem as long as your key ups
are not long winded.

I think the GPN6145A is made by MagneTek.

Its the 2A for 4 minutes spec thats a bit worrying - especially in relation to the 3.6A continuous spec.....it implies that you can only draw 2A for 4 minutes BUT 3.6A continuously???? If you can only draw 2A for 4 minutes, how long can you draw 1A??

I guess my Moto stuff will draw 1A RX and 6A TX

Motorola GPN6133A 13.8 VDC @ 6 amps. Rated for 4 minutes at 2 amps, and 1 minute at 10 amps. Input 95-132 or 198-255 VAC 47-63 Hz.. Power supply has built in overload and short circuit protection, and auto recovery at 10 amps.

4 minutes at 2A seems very poor for a fair sized switch mode PSU. A small cheap LCD TV switch mode will run 4A continuously.

If its only 2A for 4 minutes, how long for 1A? ie RXing continuously.

I also saw mention in some spec info of 3.6A continuously????

Maybe the spec is wrong - maybe it should be 8A for 4 minutes NOT 2A??

I am not sure why you have such doubts about this supply.

I gather you want to use a CDM1250 from your first post in this thread
and if it is a 25W radio i think you should probably be ok.

The thing to bear in mind is that most key ups at high current draw are
usually short and that gives the electronics time to cool back down while
radiating the heat into the surrounding air from the PS heat sinks.

Its just the 2A for 4 minutes spec

For example, I think my MaxTrax pulls 1.5A on RX - so is it safe to use the PSU??

I'm sure 2A for 4 minutes is wrong??...it justs seems much too low...8A for 4 minutes seems more reasonable.

g8tzl2004 wrote:Its just the 2A for 4 minutes spec

For example, I think my MaxTrax pulls 1.5A on RX - so is it safe to use the PSU??

I'm sure 2A for 4 minutes is wrong??...it justs seems much too low...8A for 4 minutes seems more reasonable.

A maxtrac for rx only will be a pretty safe bet - should be no problem at all.

Same for a CDM1250.

If you are going to tx with either of them if it is a 25W radio just keep your
tx time short (like less than a minute) and you should still be ok.

If it is a higher power wattage transmitter then that could pose a problem
unless you adjust the power out to a lower wattage.

Thanks

Do you think the 2A for 4 minutes spec is wrong?

g8tzl2004 wrote:Thanks

Do you think the 2A for 4 minutes spec is wrong?

Over the years i have seen many a doc error from moto but
i would only be speculating if i said yes or no to your question
and i do not like to speculate unless it is absolutely necessary.