Every motor must be protected from all possible faults to ensure prolonged and safe operation as well as time loss caused due to breakdown. Almost all the industries rely on the electric motor to control its processes and production. Hence it is necessary to make the motor fail-safe.
The time taken by them to open the contactor during overloads is specified by the trip class. It is commonly classified into Class 10, Class 20, Class 30 and Class 5. The OLR trips in 10 seconds, 20 seconds, 30 seconds and 5 seconds respectively at 600% of full load current to the motor. Class 10 and Class 20 are very commonly used ones. Class 30 overload relay are used for protection of motors driving high inertia loads and Class 5 relay are used for the motors requiring very fast tripping.
| 1.058 * Ir | 1.2 * Ir | 1.5 * Ir | 7.2 * Ir | |
|---|---|---|---|---|
| Class | Time to trip from a cold start | |||
| 10A | >hr | <2hr | <2min | 2s |
| 10 | >2hr | <2hr | <4min | 2s |
| 20 | >2hr | <2hr | 8min | 2s |
| 30 | >2hr | <2hr | <12min | 2s |
As discussed above, there are three major conditions for overload trips:
Apart from these, there may be some additional protection feature available. This varies from one manufacturer to the other.
During normal operation, the current flowing through each pole of an overload relay to the motor remains the same at a time. If anyone of the phase is interrupted, the current through the other two phases rises to 1.73 times the normal value. Hence the overload relay gets heated up and it trips. Phase failure is also known as single phasing of motoror phase loss.
Overload relay cannot protect against short circuits. They should always be used with short circuit protection devices. Otherwise, any short circuits in the motor can potentially damage them. They can protect against overloads, phase loss, and phase imbalance, but not short circuits.
Overload relay is a device that can protect a motor from overloads, phase failure and phase imbalances. Based on the principle of operation they are classified into thermal and electronic overload relay.Thermal OLRis based on the principle of deformation of a bimetallic strip on heating and the electronic overload relay is a microprocessor-based device.
1 - Electronic Overload relay manufacturer In A.G.COLLEGE Hyderabad
2 - Electronic Overload relay manufacturer In A.GS OFFICE Hyderabad
3 - Electronic Overload relay manufacturer In A.GS. STAFF QUARTERS Hyderabad
4 - Electronic Overload relay manufacturer In ADMINISTRATIVE BUILDINGS Hyderabad
5 - Electronic Overload relay manufacturer In AFZALGUNJ Hyderabad
6 - Electronic Overload relay manufacturer In ALIABAD Hyderabad
7 - Electronic Overload relay manufacturer In AMBERNAGAR Hyderabad
8 - Electronic Overload relay manufacturer In AMBERPET Hyderabad
9 - Electronic Overload relay manufacturer In ANANDNAGAR Hyderabad
10 - Electronic Overload relay manufacturer In ANANTAGIRI Hyderabad
11 - Electronic Overload relay manufacturer In ANANTARAM Hyderabad
12 - Electronic Overload relay manufacturer In ANDHRA MAHILA SABHA Hyderabad
13 - Electronic Overload relay manufacturer In ANKIREDDIPALLI Hyderabad
14 - Electronic Overload relay manufacturer In ANKUSHAPUR Hyderabad
15 - Electronic Overload relay manufacturer In ANNAJIGUDA Hyderabad
16 - Electronic Overload relay manufacturer In APERL Hyderabad
17 - Electronic Overload relay manufacturer In APHB COLONY MOULALI Hyderabad
18 - Electronic Overload relay manufacturer In ASHOKNAGAR Hyderabad
19 - Electronic Overload relay manufacturer In ATTAPUR Hyderabad
20 - Electronic Overload relay manufacturer In ATVELLI Hyderabad
21 - Electronic Overload relay manufacturer In BADANGPET Hyderabad
22 - Electronic Overload relay manufacturer In BAHADURPURA Hyderabad
23 - Electronic Overload relay manufacturer In BALAPUR Hyderabad
24 - Electronic Overload relay manufacturer In BANJARA HILLS Hyderabad
25 - Electronic Overload relay manufacturer In BARKATPURA Hyderabad
26 - Electronic Overload relay manufacturer In BAZARGHAT Hyderabad
27 - Electronic Overload relay manufacturer In BEGUMBAZAR Hyderabad
28 - Electronic Overload relay manufacturer In BEGUMPET Hyderabad
29 - Electronic Overload relay manufacturer In BEGUMPET POLICELINES Hyderabad
30 - Electronic Overload relay manufacturer In BHARAT NAGAR COLONY Hyderabad
31 - Electronic Overload relay manufacturer In BHOLAKPUR Hyderabad
32 - Electronic Overload relay manufacturer In BODUPPAL Hyderabad
33 - Electronic Overload relay manufacturer In BOGARAM Hyderabad
34 - Electronic Overload relay manufacturer In CENTRAL POLICE LINES Hyderabad
35 - Electronic Overload relay manufacturer In CENTRAL SECRETARIAT Hyderabad
36 - Electronic Overload relay manufacturer In CHANCHALGUDA Hyderabad
37 - Electronic Overload relay manufacturer In CHANDULALBARADARI Hyderabad
38 - Electronic Overload relay manufacturer In CHERIAL Hyderabad
39 - Electronic Overload relay manufacturer In CHERLAPALLI Hyderabad
40 - Electronic Overload relay manufacturer In CRP CAMP Hyderabad
41 - Electronic Overload relay manufacturer In CYBERABAD Hyderabad
42 - Electronic Overload relay manufacturer In DABIRPUR Hyderabad
43 - Electronic Overload relay manufacturer In DARGAH HUSSAIN SHAHWALI Hyderabad
44 - Electronic Overload relay manufacturer In DARUSHIFA Hyderabad
45 - Electronic Overload relay manufacturer In DATTATREYA COLONY Hyderabad
46 - Electronic Overload relay manufacturer In DHOOLPET Hyderabad
47 - Electronic Overload relay manufacturer In DILSUKHNAGAR COLONY Hyderabad
48 - Electronic Overload relay manufacturer In DR AS RAO NAGAR Hyderabad
49 - Electronic Overload relay manufacturer In ECIL Hyderabad
50 - Electronic Overload relay manufacturer In ERRAGADDA Hyderabad
51 - Electronic Overload relay manufacturer In FALAKNUMA Hyderabad
52 - Electronic Overload relay manufacturer In FATEHDARWAZA Hyderabad
53 - Electronic Overload relay manufacturer In FATHENAGAR COLONY Hyderabad
54 - Electronic Overload relay manufacturer In GAGAN MAHAL Hyderabad
55 - Electronic Overload relay manufacturer In GAJULARAMARAM Hyderabad
56 - Electronic Overload relay manufacturer In GANDHI BHAWAN Hyderabad
57 - Electronic Overload relay manufacturer In GANDHINAGAR Hyderabad
58 - Electronic Overload relay manufacturer In GHATKESAR Hyderabad
59 - Electronic Overload relay manufacturer In GIRMAPUR Hyderabad
60 - Electronic Overload relay manufacturer In GOLCONDA Hyderabad
61 - Electronic Overload relay manufacturer In GOLCONDA CHOWRASTHA Hyderabad
62 - Electronic Overload relay manufacturer In GOWDAVALLI Hyderabad
63 - Electronic Overload relay manufacturer In GSI(SR) BANDLAGUDA Hyderabad
64 - Electronic Overload relay manufacturer In HANUMANPET Hyderabad
65 - Electronic Overload relay manufacturer In HASANNAGAR Hyderabad
66 - Electronic Overload relay manufacturer In HIGH COURT Hyderabad
67 - Electronic Overload relay manufacturer In HIMAYATHNAGAR Hyderabad
68 - Electronic Overload relay manufacturer In HIMMATNAGAR Hyderabad
69 - Electronic Overload relay manufacturer In HINDI BHAWAN Hyderabad
70 - Electronic Overload relay manufacturer In HINDUSTAN CABLES LTD Hyderabad
71 - Electronic Overload relay manufacturer In HUDA RESIDENTIAL COMPLEX Hyderabad
72 - Electronic Overload relay manufacturer In HUMAYUNNAGAR Hyderabad
73 - Electronic Overload relay manufacturer In HUSSAINIALAM Hyderabad
74 - Electronic Overload relay manufacturer In HYD AIRPORT II Hyderabad
75 - Electronic Overload relay manufacturer In HYD AIRPORT I Hyderabad
76 - Electronic Overload relay manufacturer In HYDER SHAH KOTE Hyderabad
77 - Electronic Overload relay manufacturer In HYDERABAD JUBILEE Hyderabad
78 - Electronic Overload relay manufacturer In HYDERABAD PUBLIC SCHOOL Hyderabad
79 - Electronic Overload relay manufacturer In HYDERABAD. Hyderabad
80 - Electronic Overload relay manufacturer In HYDERGUDA Hyderabad
81 - Electronic Overload relay manufacturer In I.E.NACHARAM Hyderabad
82 - Electronic Overload relay manufacturer In I.M.COLONY Hyderabad
83 - Electronic Overload relay manufacturer In IICT Hyderabad
84 - Electronic Overload relay manufacturer In IBRAHIM BAGH LINES Hyderabad
85 - Electronic Overload relay manufacturer In IE MOULALI Hyderabad
86 - Electronic Overload relay manufacturer In JAGGAMGUDA Hyderabad
87 - Electronic Overload relay manufacturer In JAMA I OSMANIA Hyderabad
88 - Electronic Overload relay manufacturer In JEEDIMETLA Hyderabad
89 - Electronic Overload relay manufacturer In JILLELLAGUDA Hyderabad
90 - Electronic Overload relay manufacturer In JNTU KUKAT PALLY Hyderabad
91 - Electronic Overload relay manufacturer In JUBILEE HILLS Hyderabad
92 - Electronic Overload relay manufacturer In KAKATIYA NAGAR Hyderabad
93 - Electronic Overload relay manufacturer In KANCHANBAGH Hyderabad
94 - Electronic Overload relay manufacturer In KARMANGHAT Hyderabad
95 - Electronic Overload relay manufacturer In KARWAN SAHU Hyderabad
96 - Electronic Overload relay manufacturer In KATCHVANISINGARAM Hyderabad
97 - Electronic Overload relay manufacturer In KATTEDAN IE Hyderabad
98 - Electronic Overload relay manufacturer In KEESARA Hyderabad
99 - Electronic Overload relay manufacturer In KEESARAGUTTA Hyderabad
100 - Electronic Overload relay manufacturer In KESHOGIRI Hyderabad
101 - Electronic Overload relay manufacturer In KHAIRATABAD Hyderabad
102 - Electronic Overload relay manufacturer In KHAPRA Hyderabad
103 - Electronic Overload relay manufacturer In KINGSWAY Hyderabad
104 - Electronic Overload relay manufacturer In KISHANBAGH Hyderabad
105 - Electronic Overload relay manufacturer In KISMATHPUR Hyderabad
106 - Electronic Overload relay manufacturer In KOLTHUR Hyderabad
107 - Electronic Overload relay manufacturer In KORREMAL Hyderabad
108 - Electronic Overload relay manufacturer In KULSUMPURA Hyderabad
109 - Electronic Overload relay manufacturer In KUSHAIGUDA Hyderabad
110 - Electronic Overload relay manufacturer In KUTBULLAPUR Hyderabad
111 - Electronic Overload relay manufacturer In KYASARAM Hyderabad
112 - Electronic Overload relay manufacturer In L B NAGAR Hyderabad
113 - Electronic Overload relay manufacturer In LIC DIVISION Hyderabad
114 - Electronic Overload relay manufacturer In LALGADI MALAKPET Hyderabad
115 - Electronic Overload relay manufacturer In LALLAGUDA Hyderabad
116 - Electronic Overload relay manufacturer In LALLAPET Hyderabad
117 - Electronic Overload relay manufacturer In LUNGER HOUSE Hyderabad
118 - Electronic Overload relay manufacturer In MG ROAD Hyderabad
119 - Electronic Overload relay manufacturer In MADHAPUR Hyderabad
120 - Electronic Overload relay manufacturer In MALAKPET COLONY Hyderabad
121 - Electronic Overload relay manufacturer In MALLAPUR Hyderabad
122 - Electronic Overload relay manufacturer In MAMIDIPALLI Hyderabad
123 - Electronic Overload relay manufacturer In MANGALHAT Hyderabad
124 - Electronic Overload relay manufacturer In MANSOORABAD Hyderabad
125 - Electronic Overload relay manufacturer In MOAZZAMPURA Hyderabad
126 - Electronic Overload relay manufacturer In MOGHALPURA Hyderabad
127 - Electronic Overload relay manufacturer In MOOSAPET Hyderabad
128 - Electronic Overload relay manufacturer In MOULALI Hyderabad
129 - Electronic Overload relay manufacturer In MUDCHINTANAPALLI Hyderabad
130 - Electronic Overload relay manufacturer In MURAD NAGAR Hyderabad
131 - Electronic Overload relay manufacturer In MUSHEERABAD DSO Hyderabad
132 - Electronic Overload relay manufacturer In MUSHEERABAD NDSO Hyderabad
133 - Electronic Overload relay manufacturer In NALLAKUNTA Hyderabad
134 - Electronic Overload relay manufacturer In NANAKRAMGUDA Hyderabad
135 - Electronic Overload relay manufacturer In NAPIER LINES Hyderabad
136 - Electronic Overload relay manufacturer In NARAYANGUDA Hyderabad
137 - Electronic Overload relay manufacturer In NEHRUNAGAR Hyderabad
138 - Electronic Overload relay manufacturer In NEW MARUTHI NAGAR Hyderabad
139 - Electronic Overload relay manufacturer In NEW MLA QUARTERS Hyderabad
140 - Electronic Overload relay manufacturer In NEW NALLAKUNTA Hyderabad
141 - Electronic Overload relay manufacturer In NGRI Hyderabad
142 - Electronic Overload relay manufacturer In NIMBOLIADDA Hyderabad
143 - Electronic Overload relay manufacturer In NUTANKAL Hyderabad
144 - Electronic Overload relay manufacturer In OLD MALAKPET Hyderabad
145 - Electronic Overload relay manufacturer In OLD MLA QUARTERS Hyderabad
146 - Electronic Overload relay manufacturer In OSMANIA GENERAL HOSPITAL Hyderabad
147 - Electronic Overload relay manufacturer In OSMANNAGAR Hyderabad
148 - Electronic Overload relay manufacturer In P & T COLONY Hyderabad
149 - Electronic Overload relay manufacturer In PADMARAONAGAR Hyderabad
150 - Electronic Overload relay manufacturer In PADMAVATHI NAGAR Hyderabad
151 - Electronic Overload relay manufacturer In PAHADISHAREEF Hyderabad
152 - Electronic Overload relay manufacturer In PARISHRAM BHAWAN Hyderabad
153 - Electronic Overload relay manufacturer In PEDALAXMAPUR Hyderabad
154 - Electronic Overload relay manufacturer In PEERZADIGUDA Hyderabad
155 - Electronic Overload relay manufacturer In PICKET Hyderabad
156 - Electronic Overload relay manufacturer In PRAGATINAGAR Hyderabad
157 - Electronic Overload relay manufacturer In PRAKASHAMNAGAR Hyderabad
158 - Electronic Overload relay manufacturer In PRATAPSINGARAM Hyderabad
159 - Electronic Overload relay manufacturer In PUTLIBOWLI Hyderabad
160 - Electronic Overload relay manufacturer In QUAZIPURA Hyderabad
161 - Electronic Overload relay manufacturer In R.C.IMARAT Hyderabad
162 - Electronic Overload relay manufacturer In RAHMATH NAGAR Hyderabad
163 - Electronic Overload relay manufacturer In RAIL NILAYAM Hyderabad
164 - Electronic Overload relay manufacturer In RAJ BHAWAN Hyderabad
165 - Electronic Overload relay manufacturer In RAJBOLARAM Hyderabad
166 - Electronic Overload relay manufacturer In RAJENDRANAGAR Hyderabad
167 - Electronic Overload relay manufacturer In RAMAKRISHANAPURAM Hyderabad
168 - Electronic Overload relay manufacturer In RAMAKRISHNA MUTT Hyderabad
169 - Electronic Overload relay manufacturer In RAMKOTI Hyderabad
170 - Electronic Overload relay manufacturer In RAMPALLIDIARA Hyderabad
171 - Electronic Overload relay manufacturer In RANGAREDDY DT COURTS Hyderabad
172 - Electronic Overload relay manufacturer In RAVALKOL Hyderabad
173 - Electronic Overload relay manufacturer In REINBAZAR Hyderabad
174 - Electronic Overload relay manufacturer In ROMPALLI Hyderabad
175 - Electronic Overload relay manufacturer In SAHIFA Hyderabad
176 - Electronic Overload relay manufacturer In SAIDABAD Hyderabad
177 - Electronic Overload relay manufacturer In SAIDABAD COLONY Hyderabad
178 - Electronic Overload relay manufacturer In SAINAGAR Hyderabad
179 - Electronic Overload relay manufacturer In SAKKUBAI NAGAR Hyderabad
180 - Electronic Overload relay manufacturer In SANATH NAGAR COLONY Hyderabad
181 - Electronic Overload relay manufacturer In SANATHNAGAR I E Hyderabad
182 - Electronic Overload relay manufacturer In SANJEEV REDDY NAGAR Hyderabad
183 - Electronic Overload relay manufacturer In SANTOSHNAGAR COLONY Hyderabad
184 - Electronic Overload relay manufacturer In SAROORNAGAR Hyderabad
185 - Electronic Overload relay manufacturer In SECUNDERABAD Hyderabad
186 - Electronic Overload relay manufacturer In SEETHARAMPET Hyderabad
187 - Electronic Overload relay manufacturer In SEMINARY Hyderabad
188 - Electronic Overload relay manufacturer In SHAHALIBANDA Hyderabad
189 - Electronic Overload relay manufacturer In SHANTINAGAR Hyderabad
190 - Electronic Overload relay manufacturer In SHIVARAMPALLI Hyderabad
191 - Electronic Overload relay manufacturer In SHYAM NAGAR Hyderabad
192 - Electronic Overload relay manufacturer In SITAPHALMANDI Hyderabad
193 - Electronic Overload relay manufacturer In SNEHAPURI COLONY Hyderabad
194 - Electronic Overload relay manufacturer In SOMAJIGUDA Hyderabad
195 - Electronic Overload relay manufacturer In SOUTH BANJARA HILLS Hyderabad
196 - Electronic Overload relay manufacturer In SRINAGAR COLONY Hyderabad
197 - Electronic Overload relay manufacturer In SRINIVASAPURAM Hyderabad
198 - Electronic Overload relay manufacturer In SRIPURAM COLONY Hyderabad
199 - Electronic Overload relay manufacturer In STATE BANK OF HYDERABAD Hyderabad
200 - Electronic Overload relay manufacturer In STATE BANK OF INDIA Hyderabad
201 - Electronic Overload relay manufacturer In STN KACHIGUDA Hyderabad
202 - Electronic Overload relay manufacturer In SULTANSHAHI Hyderabad
203 - Electronic Overload relay manufacturer In SURARAM Hyderabad
204 - Electronic Overload relay manufacturer In SURVEY OF INDIA Hyderabad
205 - Electronic Overload relay manufacturer In SVPNPA Hyderabad
206 - Electronic Overload relay manufacturer In SWARAJYANAGAR Hyderabad
207 - Electronic Overload relay manufacturer In TADBUN Hyderabad
208 - Electronic Overload relay manufacturer In TAGARIKANAKA Hyderabad
209 - Electronic Overload relay manufacturer In TARNAKA Hyderabad
210 - Electronic Overload relay manufacturer In THIMMAIPALLI Hyderabad
211 - Electronic Overload relay manufacturer In THUMKUNTA Hyderabad
212 - Electronic Overload relay manufacturer In TOLI CHOWKI Hyderabad
213 - Electronic Overload relay manufacturer In TURKAPALLIYADARAM Hyderabad
214 - Electronic Overload relay manufacturer In UPPAL Hyderabad
215 - Electronic Overload relay manufacturer In UPPUGUDA Hyderabad
216 - Electronic Overload relay manufacturer In VAIDEHINAGAR Hyderabad
217 - Electronic Overload relay manufacturer In VAISHALINAGAR Hyderabad
218 - Electronic Overload relay manufacturer In VANASTALIPURAM Hyderabad
219 - Electronic Overload relay manufacturer In VENGAL RAO NAGAR Hyderabad
220 - Electronic Overload relay manufacturer In VIDHAN SABHA Hyderabad
221 - Electronic Overload relay manufacturer In VIDYANAGAR Hyderabad
222 - Electronic Overload relay manufacturer In VIJAY NAGAR COLONY Hyderabad
223 - Electronic Overload relay manufacturer In VIKARABAD Hyderabad
224 - Electronic Overload relay manufacturer In YADGARPALLI Hyderabad
225 - Electronic Overload relay manufacturer In YAKUTPURA Hyderabad
226 - Electronic Overload relay manufacturer In YOUSUFGUDA Hyderabad
227 - Electronic Overload relay manufacturer In ZAMISTANPUR Hyderabad
228 - Electronic Overload relay manufacturer In ZINDATELISMATH Hyderabad
