Do mo:la khoang cach giua tiep diem dong va tiep diem tinh o vi tri ngat cua kcd.Phai chon do mo phu hop dam bao dap tat ho quang nhung kick thuoc,khoi luong cua co cau truyen dong dien lai dat toi uu.Coi cong tac to dong dien I=40-600A,die nap 500v co the chon m=6-12mm.

Do lun: la quang duong di them duoc cua tiep diem dong neu ko co tiep diem tinh can lai.Can thiet phai co do lun cua tiep diem de co luc ep tiep diem va trong qua trinh lam viec tiep diem bi an mon,tiep diem van dam bao tiep xuc tot.Nhu vay phai chon do lun cua tiep diem lon hon do cao bi an mon cua tiep diem(l>h).Thuong chon l=(1,5-2,5)h

Theo LT: l=A+B.Idm(mm) A=1,5mm B=0,02 mm/A

Theo kinh nghiem: Idm=100,150,300,600 thi l=2.3-3.5,3-4,4-5,5-6.

Khoang lan : la quang duong ma tiep diem dong di chuyen(1 cung tron tren mat tiep diem tinh)No thuong dc dung o dang tiep diem kieu ngon,thuong duoc dung thay the cho tiep diem ho quang vi do co khoang lan lam cho diem lam viec cua tiep diem khac diem ho quang chay.x=3-12 mm\

Khoang truot : La quang duong ma tiep diem dong truot tren be mat tiep diem tinh,do co khoang truot ma be mat tiep xuc dc lam sach,dc su dung trong tiep diem dang ngon. y=0.2-1.5 mmm. Neu tang y se tang do mon tiep diem vi vay phai su dung ket hop khoang lan va truot cho phu hop.