Capacitors marked "NP" can flow in both directions and are called Bi-Polar or Non-Polarized.
Unfortunately most Direct Current "DC" NonPolarized caps are big and don't fit "artfully" into your machine. Notice that these Blue Non-polarized capacitors are much bigger than polarized capacitors.
The over-all physical size is determined by the V (Volt) rating (which is the maximum voltage it can stand without failing) and the storage capacity, mf, the amount it will store. We never run 50 Volts in a machine so a 50 Volt maximum is overkill. Unfortunately DC NPs are not so available in smaller overall sizes but the polarized type are. The literature indicates that large value Voltage does not adversely effect performance. However, for the tattoo machine you may notice some differences. For safety, Unimax installs Bi-Polar capacitors in all Unimax Branded standard machines.
Soldering capacitors without using a heat sink is likely to ruin a capacitor before you even use it. If you install a capacitor and it is sparking, it may already be bad from getting too much heat. Try again putting a heat sink between the capacitor and the soldering iron.
Knowing the problem with heat and soldering capacitors, in the early 90s, Unimax began making and introduced commercially available pre-soldered capacitors with forked ends for easy replacements.
It is also a good way to experiment and see how different value capacitors effect performance. You should try it.
It is generally reported that
capacitor failures can be attributed to:
1) Heating, causing a capacitor to swell and explode.
2) Drying of the liquid electrolytic inside from various causes, such as
defects, leaking and even cleaning.
3) Capacitors re-form over time to meet a usual and expected voltage.
Surges that are not normal can cause sudden failure.
4) The older they get the greater the incidence of failure.
Before using a new capacitor run your machine putting your finger on the capacitor and feeling if it starts to get hot. You will know within a few seconds. "Hot" is excess heat. Capacitors should not feel hot to the touch.
Do not run your machine if the capacitor feels hot to the touch.
The purpose of the capacitor (or diode) is to absord the reverse voltage
surge and dissipate it quickly. It is there to prevent burning holes in
your front spring.
You can though run a coil machine with a lot of sparking.
Before the late 80's there were no capacitors used and all machines sparked. They eat a hole through the front spring where the sparking is.
The first silver "contact points" (I believe by Spaulding) were put in a hole made in the front spring so that the sparking would eat the contact point and then you would replace the silver contact point instead of eating the spring up.
Capacitors then became the standard way to deal with reverse voltage.
The letters "NP"
printed on the case means "Non-Polarized": the electricity can flow in
either direction. See the top 4 Blue samples.
An arrow printed on
the cover means "Polarized" the electricity must
flow in the
direction of the arrow that is printed on the capacitor body.
Bottom three Green samples.
If electricity flows in the wrong direction (against the arrow) it may heat
up, fail, explode or "pop." Heat decreases the effectiveness
of a capacitor and can lead to failure spewing the contents of
the capacitor in your face or eyes. Hopefully the capacitor will be
covered by some shrink wrap.
Your power supply has (-) Black and (+) Red output
terminals (and sometimes a ground-green).
Those little electrons flow out the negative(-) and back
into the positive(+). The direction of the electricity is from the
negative to the positive in that direction.
It is important that you orient your clip cord so that the electricity
will flow in the direction of the arrow for polarize capacitors. But after your clip cord gets all twisted how can you tell which is
which.
Hook up your machine and run it keeping your finger on the capacitor.
If it starts to heat up switch your clip cord around and mark the clip
cord so that you know
which way it should go.
We have both Polarized and Non-Polarized Capacitors in stock and can fit your new machine with any size or type of capacitor.
If you use a Tattanator power supply capacitors are obsolete for your coil machine because it has built in diodes to prevent the reverse voltage.