Each alloy powder core of DONGBU is coated with epoxy resin and marked with a part number except sendust powder core.
Part numer means core identification and it includes name code of materials, core dimension code, apparent inducance code, temperature stability code, guaranteed breakdown voltage code adn inductance tolerance band code.
Core identification for easy distinction is following as below:
 
Normally, name code of materials, outer diameter of bare core, apparent inductance in 1,000 turns adn inductance temperature stability are stamped on the outside of the core.
But, for customer order, breakdown voltage and tolerance band of apparent inductance are marked in label.
EXAMPLE OF CORE IDENTIFICATION
 
 
NAME CODE OF MATERIALS AND COLOR OF TOROIDAL CORE
Material name code of material and color are following as below:
MOLYPERMALLOY POWDER CORE : M (Gray)
SENDUST POWDER CORE : S (Black)
HIGH FLUX POWDER CORE : H (Khaki)
POWER FLUX CORE : W (Bluish Green)
 
OUTER DIAMETER OF COATED CORE
 
It means diameter of toroidal core. (first 3 digits in 1/100 inches)
¡Ø please see specification table for detailed term
 
APPARENT INDUCTANCE IN 1,000 TURNS
It means apparent inductance of toroidal core.
(3 digits of apparent inductance is value in mH per 1,000 turns)
 
BREAKDOWN VOLTAGE
 
It means breakdown voltage of core and is following as the below table2 :
 
Table 2. BREAKDOWN VOLTAGE.
CODE GUARANTEED BREAKDOWN VOLTAGE
NO MARK >500Volts
1 >1,000Volts
2 >2,000Volts
3 >4,000Volts
 
TOLERANCE OF APPARENT INDUCTANCE
 
It means tolerance of apparent inductance and is following as the below table3 :
 
Table 3. TOLERANCE OF APPARENT INDUCTANCE.
CODE TOLERANCE OF APPARENT INDUCTANCE
(DEVIATION FROM NOMINAL, %)
NO MARK +8% - -8%
+ +8% - -0%
- +0% - -8%
+8 +8% - -7%
+6 +7% - -5%
+4 +5% - -3%
+2 +3% - -1%
0 +1% - -1%
-2 +1% - -3%
-4 +3% - -5%
-6 +5% - -7%
-8 +7% - -8%