Properties of RISHO cast resin transformers

 

■Glass reinforced windings

reinforced winding

▲Glass reinforced winding(Closs section)

 

 

self-extingishing

▲Self-extinguishing proprty

Windings of RISHO cast resin transformers are reinforced with glass fabric.

And these windings are also insulated with epoxy resin.

Therefore,RISHO cast resin transformers are excellent in moisture and anti-pollution property

Dimensions & Weight are smaller than oil-insulatin transformers.

 

■High reliable insulation system

Glass reinforced windings are insulated with Vacuum casting method.

And eoxy resin used for this insulation has low-viscosity property.

Therefore,windings of RISHO cast resin transformers has few void inside where patrial discharge occurs.

 

■Self-extinguishing

Epoxy resin used for insulation has self-extinguishing property.

Therefore,over 9200 RISHO cast resin transformers have been installed in Public facilities, such as Hospital ,Library or School up to today.

 

■Suitable for outdoor cubicle

Epoxy resin used for insulation has so excellent low water absorption property of 0.05 ～0.08% that RISHO cast resin transformers can be installed in cubicle of JIS C 4620 compliance.

 

 

 

 

■Property comparison of Cast transformers with Non cast transformers

Production

method

 Properties

Comparison

 Memo
◎:Excellent　○:Good　△:Poor
Insulation

Moisture resistance

&

Anti-pollution

 Maintenance
Cast

RISHO

method

 Windings are reinforced with glass fiber and insulated with low viscosity epoxy resin by Vacuum casting method.

◎

Voidless

◎

Low water absorption

◎

Flat winding sueface can be wiped easily

 Fiber reinforced windings are excellent in clack resistance

General

method

 Windingds are insulated with epoxy resin containing filler(sillica) by Vacuum casting method.

○

Voidless

◎

Low water

absorption

◎

Flat winding sueface can be wiped easily

 Windings have to be reinforced against cracks

Non

Cast

Prepreg

method

Windings are insulated with resin pre-impregnated glass tapes(So-called Prepreg).

Therefore resin do not thoroughly penetrate into windings

△

Parts where tap terminals are attached can not be insulated entirely

△

Rough winding surface can not be wiped easily

 

Inslation resin is apt to contain voids

 

■Durable against water extinguishing

As the test result of sprinkling test (Stained water), RISHO cast resin transformer was proved to withstand water extinguishing.

 

■Air duct structure

Excellent in radiation property with unique air dust structure.

 

■Excellent in quake resistance

RISHO cast resin transformers can be made to have heavy duty structure up to a quake of 2000 gal

 

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sprinkling

▲Sprinkling test

air duct

▲Air duct for radiation

heavy duty structure

▲Heavy duty structure

 

■Property comparison of resin cast transformer with Oil insulation transformer (6kV)
Comparison items

Cast resin

(RISHO transformers)

 Oil insulation transformers
Insulation class F A
Temp. rise limit of windings 95K 55K
Installation location Indoor only Indoor / Outdoor
Explodability Non explosive Possible
Flammability Flame retardant Flammable
Moisture resistance Non-hygroscopic

Hygroscopic

(Respiration type)
Noise level（ｄB） 63 56
Short circuit strength Excellent Good
Insulation property Stable stable
Insulation structure

Glass fabric and Epoxy resin

(Composit strcture)

 Paper & Insulation oil
Strengt of windings to external force Excellent (Protected by Case)
Quake resistance Excellent Good
Impluse resistance Excellent Excellent

Maintenance

(Regular check items)

1.Wiping or Vacuume cleaning

2.Visual appearance

3.Temperature

1.Isulation oil

2.Filtering of insulation oil

3.Oil level and Oil leak

4.Temperature

5.Oil change as necessary

 

■Easy onsite assembly for replacement

arriva

▲Arrival

RISHO cast resin transformers can be assembled on site.

Therefore, even though shortage of capacity of transformer comes about,replacement for transformer with larger capacity could be achieved easily.

 

e core

▲E core

coil inserting

▲Coil inserting

completion

▲Completion