My Ranger is blowing the 5 amp primary fuse every once in a while when
I turn it on. I have checked for any kind of intermittent short but
unable to find anything. I am now suspecting inrush current. My Ranger
has all the power supply mods. Solid state HV and LV power supplies
with 330mfd LV cap and 165mfd HV cap. At first did not suspect inrush
current due to having choke input filters but I suppose with the solid
state rectifiers and the large caps it maybe happening. Does anyone
have any suggestions to limit this inrush current in the Ranger. Also,
does anyone know what the Ranger's nominal current consumption is from
the 117 VAC source under full load? Any info is appreciated. 73, Randy

"wb5kcm" wrote in message
ups.com...
My Ranger is blowing the 5 amp primary fuse every once in
a while when
I turn it on. I have checked for any kind of intermittent
short but
unable to find anything. I am now suspecting inrush
current. My Ranger
has all the power supply mods. Solid state HV and LV power
supplies
with 330mfd LV cap and 165mfd HV cap. At first did not
suspect inrush
current due to having choke input filters but I suppose
with the solid
state rectifiers and the large caps it maybe happening.
Does anyone
have any suggestions to limit this inrush current in the
Ranger. Also,
does anyone know what the Ranger's nominal current
consumption is from
the 117 VAC source under full load? Any info is
appreciated. 73, Randy


You might try a slow blow fuse. You could be right
about the inrush current with the solid state recifiers and
much larger than original caps.


--
---
Richard Knoppow
Los Angeles, CA, USA




--
Posted via a free Usenet account from http://www.teranews.com

On Apr 12, 11:52 am, "Richard Knoppow" wrote:
"wb5kcm" wrote in message

ups.com...



My Ranger is blowing the 5 amp primary fuse every once in
a while when
I turn it on. I have checked for any kind of intermittent
short but
unable to find anything. I am now suspecting inrush
current. My Ranger
has all the power supply mods. Solid state HV and LV power
supplies
with 330mfd LV cap and 165mfd HV cap. At first did not
suspect inrush
current due to having choke input filters but I suppose
with the solid
state rectifiers and the large caps it maybe happening.
Does anyone
have any suggestions to limit this inrush current in the
Ranger. Also,
does anyone know what the Ranger's nominal current
consumption is from
the 117 VAC source under full load? Any info is
appreciated. 73, Randy

You might try a slow blow fuse. You could be right
about the inrush current with the solid state recifiers and
much larger than original caps.

--
---
Richard Knoppow
Los Angeles, CA, USA


--
Posted via a free Usenet account fromhttp://www.teranews.com

Thanks for the idea Richard, I may give the sloBlo fuse a try. I was
reading something where some have used a Thermistor that will limit
inrush current.? Have you or anyone ever used a thermistor in a Ranger
or other transmitter?

"wb5kcm" wrote in message
oups.com...
On Apr 12, 11:52 am, "Richard Knoppow" wrote:
"wb5kcm" wrote in message
Thanks for the idea Richard, I may give the sloBlo fuse a try. I was
reading something where some have used a Thermistor that will limit
inrush current.? Have you or anyone ever used a thermistor in a Ranger
or other transmitter?


The device you want is called an ICL, or inrush current limiter.

Peter

"wb5kcm" wrote in message
ups.com...
My Ranger is blowing the 5 amp primary fuse every once in a while when
I turn it on. I have checked for any kind of intermittent short but
unable to find anything. I am now suspecting inrush current. My Ranger
has all the power supply mods. Solid state HV and LV power supplies
with 330mfd LV cap and 165mfd HV cap. At first did not suspect inrush
current due to having choke input filters but I suppose with the solid
state rectifiers and the large caps it maybe happening. Does anyone
have any suggestions to limit this inrush current in the Ranger. Also,
does anyone know what the Ranger's nominal current consumption is from
the 117 VAC source under full load? Any info is appreciated. 73, Randy

You probably would find a varistor in the primary of the transformer to be
of help. It also improves the life of the power on-off switch at the same
time.
We used one in the primary of the Signal One transceivers after having
measured an one cycle inrush current in excess of 50 Amperes! (Hypersil core
transformer) You can purchase them that exhibit a hundred Ohms or so when
cold that drop to 4-6 Ohms hot and essentially remove themselves from the
circuit after the first few moments of operation. They don't help at all if
you turn the radio off after a period of use and immediately power it back
up whilst the varistor is still hot, but it takes the edge off the inrush
curent in "normal" operation. About the size of 3-4 nickels stacked together
with a radial lead off each face.

W4ZCB

On Apr 12, 9:43 pm, "Harold E. Johnson" wrote:
"wb5kcm" wrote in message

ups.com...

My Ranger is blowing the 5 amp primary fuse every once in a while when
I turn it on. I have checked for any kind of intermittent short but
unable to find anything. I am now suspecting inrush current. My Ranger
has all the power supply mods. Solid state HV and LV power supplies
with 330mfd LV cap and 165mfd HV cap. At first did not suspect inrush
current due to having choke input filters but I suppose with the solid
state rectifiers and the large caps it maybe happening. Does anyone
have any suggestions to limit this inrush current in the Ranger. Also,
does anyone know what the Ranger's nominal current consumption is from
the 117 VAC source under full load? Any info is appreciated. 73, Randy

You probably would find a varistor in the primary of the transformer to be
of help. It also improves the life of the power on-off switch at the same
time.
We used one in the primary of the Signal One transceivers after having
measured an one cycle inrush current in excess of 50 Amperes! (Hypersil core
transformer) You can purchase them that exhibit a hundred Ohms or so when
cold that drop to 4-6 Ohms hot and essentially remove themselves from the
circuit after the first few moments of operation. They don't help at all if
you turn the radio off after a period of use and immediately power it back
up whilst the varistor is still hot, but it takes the edge off the inrush
curent in "normal" operation. About the size of 3-4 nickels stacked together
with a radial lead off each face.

W4ZCB

Thanks for the info Harold. I think that is the way I want to go is
with the ICL Thermistor or Varistor. The only thing I need is to find
out which one to use. Looking at them in the catalog, it seems the
deciding factor will be the maximum sustained current from the Ranger.
If I need a 4 amp Thermistor then it may only provide about 10 ohms
resistance depending on the current. Would 10 ohms do enough inrush
suppression? It seems the higher current models have the lowest
resistance. I will need to do a little more research into this and try
and pick the right one. Possibly two of them in series will do the
job? I have read where someone used a Thermistor p/n CL-90 on a
Hammerlund receiver with good results. This CL-90 has a 120 ohm
resistance and a 2 amp current rating. I would be concerned that this
2 amp rating would not be enough for the Ranger. Would 2 of these
CL-90's in parallel give me 60 ohms @ 4 amps??
If someone has not already tested for this. I want to check the AC
current on my Ranger at maximum AM, 100% modulation transmit. This
should give me a good idea about which ICL Thermistor to look for.
Thanks for everyones input, it is very helpful.
73, Randy, WB5KCM

wb5kcm wrote:

Thanks for the info Harold. I think that is the way I want to go is
with the ICL Thermistor or Varistor. The only thing I need is to find
out which one to use. Looking at them in the catalog, it seems the
deciding factor will be the maximum sustained current from the Ranger.
If I need a 4 amp Thermistor then it may only provide about 10 ohms

A better way is to take a relay and connect its coil, through a selected
resistor, to one of the low voltage supplies. The relay's NO contacts
should be put in series with the power line, and should have a 5 or 10 ohm
power resistor across them.

When the power is switched on, the 5 or 10 ohm resistor will be in series
with the power line, and the power supply will start to charge the filter
capacitors. When the filter capacitor's DC gets to a high enough value,
the relay will close, and apply full mains power to the primary.

This circuit has two inherent flaws: 1) if the filters get leaky, they
might never charge up enough to close the relay, and the power resistor
will overheat, and 2) the relay will draw current from your power supply.

-Chuck

On Apr 13, 8:27 am, Chuck Harris wrote:
wb5kcm wrote:
Thanks for the info Harold. I think that is the way I want to go is
with the ICL Thermistor or Varistor. The only thing I need is to find
out which one to use. Looking at them in the catalog, it seems the
deciding factor will be the maximum sustained current from the Ranger.
If I need a 4 amp Thermistor then it may only provide about 10 ohms

A better way is to take a relay and connect its coil, through a selected
resistor, to one of the low voltage supplies. The relay's NO contacts
should be put in series with the power line, and should have a 5 or 10 ohm
power resistor across them.

When the power is switched on, the 5 or 10 ohm resistor will be in series
with the power line, and the power supply will start to charge the filter
capacitors. When the filter capacitor's DC gets to a high enough value,
the relay will close, and apply full mains power to the primary.

This circuit has two inherent flaws: 1) if the filters get leaky, they
might never charge up enough to close the relay, and the power resistor
will overheat, and 2) the relay will draw current from your power supply.

-Chuck

Chuck, interesting idea using the relay. I will keep your message. I
am going to try the Thermistor and see if that will do the trick. The
concern I have with the Thermistor is if it will handle the current
that the Ranger draws and if it may cause poor regulation in the AC
side. I am going today and pickup a couple of the CL-90 Thermistors
and give them a try. I will report back possibly SUnday with the
results. If the Thermistor doesnt work, I may build up something like
your relay idea into an external metal box and use this. 73, Randy

wb5kcm wrote:
Chuck, interesting idea using the relay. I will keep your message. I
am going to try the Thermistor and see if that will do the trick. The
concern I have with the Thermistor is if it will handle the current
that the Ranger draws and if it may cause poor regulation in the AC
side. I am going today and pickup a couple of the CL-90 Thermistors
and give them a try. I will report back possibly SUnday with the
results. If the Thermistor doesnt work, I may build up something like
your relay idea into an external metal box and use this. 73, Randy

If you are going to put the relay in an external box, use a 555 timer
to control the relay's coil.

-Chuck